DBF-Lecture11-Chapter12.ppt
Database Principles: Fundamentals of Design, Implementations and Management
Lecture11- CHAPTER 12: Transaction Management and Concurrency Control
Presented by Rabia Cherouk
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ObjectivesIn this chapter, you will learn:About database transactions and their propertiesWhat concurrency control is and what role it plays in maintaining the database’s integrityWhat locking methods are and how they workHow stamping methods are used for concurrency controlHow optimistic methods are used for concurrency controlHow database recovery management is used to maintain database integrity
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What is a Transaction?A transaction is a logical unit of work that must be either entirely completed or abortedSuccessful transaction changes database from one consistent state to anotherOne in which all data integrity constraints are satisfiedMost real-world database transactions are formed by two or more database requestsEquivalent of a single SQL statement in an application program or transaction
Same as Fig. 12.1 in your book
*
Same as Fig. 12.1 in your book
*
Evaluating Transaction Results Not all transactions update the databaseSQL code represents a transaction because database was accessedImproper or incomplete transactions can have devastating effect on database integritySome DBMSs provide means by which user can define enforceable constraintsOther integrity rules are enforced automatically by the DBMS
Same as Fig. 12.2 in your book
*
Figure 9.2
Same as Fig. 12.2 in your book
*
Transaction Properties
All transactions must display atomicity, consistency, durability and serializability (ACIDS).AtomicityAll operations of a transaction must be completedConsistency Permanence of database’s consistent stateIsolation Data used during transaction cannot be used by second transaction until the first is completed
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Transaction Properties (cont..)Durability Once transactions are committed, they cannot be undoneSerializabilityConcurrent execution of several transactions yields consistent resultsMultiuser databases are subject to multiple concurrent transactions
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Transaction Management with SQLANSI (American National Standard Institute) has defined standards that govern SQL database transactionsTransaction support is provided by two SQL statements: COMMIT and ROLLBACKTransaction sequence must continue until:COMMIT statement is reachedROLLBACK statement is reachedEnd of program is reachedProgram is abnormally terminated
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The Transaction LogA DBMS uses a Transaction log to store:A record for the beginning of transactionFor each transaction component: Type of operation being performed (update, delete, insert)Names of objects affected by transaction“Before” and “after” values for updated fieldsPointers to previous and next transaction log entries for the same transactionEnding (COMMIT) of the transaction
Table 12.1 in your book
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The Transaction Log
Table 12.1 in your book
*
Concurrency ControlIs the coordination o.
This document discusses database transactions and concurrency control. It defines a transaction, describes the ACID properties of atomicity, consistency, isolation, and durability. It explains the different states a transaction can be in, types of transactions, scheduling, and serializability. The document also defines concurrency control and discusses two common concurrency control protocols: shared/exclusive locking and two phase locking.
A transaction is a logical unit of work that accesses and possibly modifies the database. It includes one or more database
operations that must either all be completed or all rolled back together to maintain database consistency. Transactions must
have ACID properties - Atomicity, Consistency, Isolation, and Durability to ensure data integrity during concurrent
execution. Concurrency control techniques like locking and timestamps are used to isolate transactions and maintain
serializability. Recovery techniques use a log to roll back or redo incomplete transactions and restore the database to a
consistent state after failures.
This document discusses transaction management and concurrency control in database systems. It defines a transaction as a logical unit of work that must be completed or aborted without intermediate states. Transactions are formed by multiple database requests and must transform the database from one consistent state to another. The document outlines the properties of transactions including atomicity, durability, serializability and isolation. It also discusses concurrency control techniques like locking and time stamping methods to coordinate simultaneous transaction execution and ensure serializability.
This presentation discusses database transactions. Key points:
1. A transaction must follow the properties of atomicity, consistency, isolation, and durability (ACID). It accesses and possibly updates data items while preserving a consistent database.
2. Transaction states include active, partially committed, failed, aborted, and committed. Atomicity and durability are implemented using a shadow database with a pointer to the current consistent copy.
3. Concurrent transactions are allowed for better throughput and response time. Concurrency control ensures transaction isolation to prevent inconsistent databases.
4. A schedule specifies the execution order of transaction instructions. A serializable schedule preserves consistency like a serial schedule. Conflict and view serializability are forms
This document discusses mobile database systems and their fundamentals. It describes the conventional centralized database architecture with a client-server model. It then covers distributed database systems which partition and replicate data across multiple servers. The key aspects covered are database partitioning, partial and full replication, and how they impact data locality, consistency, reliability and other factors. Transaction processing fundamentals like atomicity, consistency, isolation and durability are also summarized.
The document discusses transaction management in database systems. It covers the ACID properties that transactions must satisfy - atomicity, consistency, isolation, and durability. It also discusses concurrency control techniques used to allow concurrent execution of transactions while preventing anomalies, including strict two-phase locking and lock-based concurrency control. Serializability is introduced as a way to ensure concurrent schedules have the same effect as serial schedules.
This document provides an overview of transaction processing and recovery in database management systems. It discusses topics like transaction processing, concurrency control techniques including locking and timestamping protocols, recovery from transaction failures using log-based recovery, and checkpoints. The key aspects covered are the ACID properties of transactions, serialization testing using precedence graphs, recoverable schedules, and concurrency control methods like locking, timestamp ordering, and validation-based protocols.
This document discusses database transactions and concurrency control. It defines a transaction, describes the ACID properties of atomicity, consistency, isolation, and durability. It explains the different states a transaction can be in, types of transactions, scheduling, and serializability. The document also defines concurrency control and discusses two common concurrency control protocols: shared/exclusive locking and two phase locking.
A transaction is a logical unit of work that accesses and possibly modifies the database. It includes one or more database
operations that must either all be completed or all rolled back together to maintain database consistency. Transactions must
have ACID properties - Atomicity, Consistency, Isolation, and Durability to ensure data integrity during concurrent
execution. Concurrency control techniques like locking and timestamps are used to isolate transactions and maintain
serializability. Recovery techniques use a log to roll back or redo incomplete transactions and restore the database to a
consistent state after failures.
This document discusses transaction management and concurrency control in database systems. It defines a transaction as a logical unit of work that must be completed or aborted without intermediate states. Transactions are formed by multiple database requests and must transform the database from one consistent state to another. The document outlines the properties of transactions including atomicity, durability, serializability and isolation. It also discusses concurrency control techniques like locking and time stamping methods to coordinate simultaneous transaction execution and ensure serializability.
This presentation discusses database transactions. Key points:
1. A transaction must follow the properties of atomicity, consistency, isolation, and durability (ACID). It accesses and possibly updates data items while preserving a consistent database.
2. Transaction states include active, partially committed, failed, aborted, and committed. Atomicity and durability are implemented using a shadow database with a pointer to the current consistent copy.
3. Concurrent transactions are allowed for better throughput and response time. Concurrency control ensures transaction isolation to prevent inconsistent databases.
4. A schedule specifies the execution order of transaction instructions. A serializable schedule preserves consistency like a serial schedule. Conflict and view serializability are forms
This document discusses mobile database systems and their fundamentals. It describes the conventional centralized database architecture with a client-server model. It then covers distributed database systems which partition and replicate data across multiple servers. The key aspects covered are database partitioning, partial and full replication, and how they impact data locality, consistency, reliability and other factors. Transaction processing fundamentals like atomicity, consistency, isolation and durability are also summarized.
The document discusses transaction management in database systems. It covers the ACID properties that transactions must satisfy - atomicity, consistency, isolation, and durability. It also discusses concurrency control techniques used to allow concurrent execution of transactions while preventing anomalies, including strict two-phase locking and lock-based concurrency control. Serializability is introduced as a way to ensure concurrent schedules have the same effect as serial schedules.
This document provides an overview of transaction processing and recovery in database management systems. It discusses topics like transaction processing, concurrency control techniques including locking and timestamping protocols, recovery from transaction failures using log-based recovery, and checkpoints. The key aspects covered are the ACID properties of transactions, serialization testing using precedence graphs, recoverable schedules, and concurrency control methods like locking, timestamp ordering, and validation-based protocols.
The document discusses concurrency control in database management systems. It defines key terms like transaction, atomicity, consistency, isolation, and durability. Transactions must have ACID properties - Atomicity, Consistency, Isolation, and Durability. Atomicity means all operations of a transaction are completed or none are. Consistency means the database remains consistent before and after a transaction. Isolation means transactions appear to execute serially despite concurrent execution. Durability means committed transactions persist even after failures.
1. Transaction Processing and Concurrency Control.pptxcalf_ville86
This document discusses transaction processing and concurrency control in database systems. It covers topics such as transactions and their properties including atomicity, consistency, isolation, and durability. It also discusses concurrency control and how locking methods work to ensure serializability by coordinating concurrent transactions through the use of locks at different levels of granularity like the database, table, page, and row levels. The scheduler establishes the execution order of operations for concurrent transactions.
This document discusses concurrency control and its protocols. Concurrency control ensures correct results from concurrent operations while maximizing performance. It addresses issues that can arise from multiple transactions executing simultaneously on the same data. The ACID rules of atomicity, consistency, isolation, and durability are explained. Common concurrency control protocols include lock-based, two phase locking, and timestamp-based protocols. Lock-based protocols use shared and exclusive locks to control access to data. Two phase locking follows a growing and shrinking phase approach. Timestamp-based protocols serialize transactions based on timestamps.
Concurrency control ensures that operations from concurrent processes generate correct results while maximizing performance. It maintains consistency when components interacting concurrently could violate one another's consistency rules. In databases, concurrency control guarantees transactions are serializable and follow the ACID properties of atomicity, consistency, isolation, and durability. Mechanisms include optimistic, pessimistic, and semi-optimistic approaches, with the goal of generating serializable schedules for concurrency and recoverability.
The document discusses transaction management in EJB. It defines transactions and the ACID properties of atomicity, consistency, isolation, and durability. It describes transaction models like flat and nested transactions. It also discusses transaction isolation levels, distributed transactions using two-phase commit protocol, and how to control transactions programmatically using the Java Transaction API in EJB.
This document discusses transaction management in SQL. It defines a transaction as a logical unit of work that must fully commit or roll back. Transactions ensure data integrity by allowing all or none of a set of SQL statements to apply. The document covers transaction outcomes, the need for transactions, locking, isolation levels, deadlocks, and how to control transactions using SQL statements.
The document discusses transactions and the ACID properties that must be ensured to maintain data integrity in a database system. It defines a transaction, provides an example of a funds transfer transaction, and explains the goals of atomicity, consistency, isolation, and durability. It discusses issues that can arise from concurrent transaction execution like inconsistent views of data and lost updates. Mechanisms like concurrency control and locking are used to preserve the ACID properties when transactions run concurrently.
1 ) a transaction is a logical unit of work each transaction is sequ.pdfkareemangels
1 ) a transaction is a logical unit of work each transaction is sequence of logical related
commands that acomplish one task and transforms the database from one consistent state into
another .transactions are atomic in other words sysbase iq executes all the statements within the
transaction as unit at the end of each transaction changes can be commited to make them
permanent for any reason if transactions do not process properly then some or all other
intermediate changes can be undone or rolled back and the user application controls under which
the changes are commited or rolled back .
4) transaction has four properties ie atomicity ,consistency , isolation and durability ie atomicity -
requires that all parts of transaction must be completed or transactions is aborted and this
property ensures that the database remains in a consistent state
consistency- indicates the permenance of database in the consistency state .
isolation - means that the data required by an executing transaction cannot be accessed by any
other transactions until the first transaction finishes this propert ensures the data consistency for
concurrently executing transactions.
durability - indicates that the database will be in permanent consistent state after the execution of
transaction
5) serialiazability- means that the series of concurrent transactions will yield the same result as if
they were executed one after another .
2) consistent databse state is one in which all data integrity constraints are satisfied to achieve a
consistence database state a transaction must take the database from one consistent state to
another .
3) the databse is designed to verify the syntactic accuracy of the database commands given by
the user to be executed by the dbms the dbms will check the database exists that the referenced
attributes exists in the selected tables , that the attribute data type are correct and so on
unfortunately the dbms is not designed to guarantee that the syntacticaly correct transaction
actually represent the real world events .
6) transaction log is a special dbms table that contains description of all the database transactions
executed by the dbms . the database transaction log plays a crucial role in maintaining database
concurrency control and integrity .the information stored in the log is used by the dbms to
recover the database after the transaction is aborted or after system failure the transaction log is
stored in different hard disks or in different media tape to prevent the failure caused by a media
error .
7) the scheduler is the dbms concept that establish the order in which concurrent database
operations are executed . the schedular interleaves the execution of the database operations to
ensure the serialiazability of transactions in other woords the schedular guarantees that the
execution of concurrent transactions will yield the same results as though the transactions were
executed one after the another .the scheduler is important because it.
This document discusses concurrency control algorithms for distributed database systems. It describes distributed two-phase locking (2PL), wound-wait, basic timestamp ordering, and distributed optimistic concurrency control algorithms. For distributed 2PL, transactions lock data items in a growing phase and release locks in a shrinking phase. Wound-wait prevents deadlocks by aborting younger transactions that wait on older ones. Basic timestamp ordering orders transactions based on their timestamps to ensure serializability. The distributed optimistic approach allows transactions to read and write freely until commit, when certification checks for conflicts. Maintaining consistency across distributed copies is important for concurrency control algorithms.
Transactions and Concurrency Control in distributed systems. Transaction properties, classification, and transaction implementation. Flat, Nested, and Distributed transactions. Inconsistent Retrievals, Lost Update, Dirty Read, and Premature Writes Problem
This document provides an overview of database transactions. It defines transactions and discusses their key concepts and states. It describes ACID properties including atomicity, consistency, isolation, and durability. It discusses implementation of atomicity and durability using shadow databases. It also covers concurrent execution, serializability, recoverability, and how transactions are defined in SQL.
The document discusses transaction processing and recovery and concurrency control in database systems. It defines a transaction as a logical unit of work that takes a database from one consistent state to another. Transactions must have the ACID properties of atomicity, consistency, isolation, and durability. Concurrency control techniques ensure transactions execute correctly and isolation despite running concurrently. Recovery techniques such as logging and checkpoints allow recovering the database to a consistent state if a failure occurs during transaction processing.
This document discusses transaction management and concurrency control in databases. It defines a transaction as a logical unit of work that must be entirely completed or aborted, with no partial states. Transactions have properties of atomicity, consistency, isolation, and durability. The document uses an example of a sales transaction to illustrate transactions and explains how the database transaction log tracks transactions to support recovery.
The document discusses concurrency control in database management systems. Concurrency control ensures that transactions are performed concurrently without conflicting results by using methods like locking and timestamps. It prevents issues like lost updates, dirty reads, and non-repeatable reads. The main concurrency control protocols discussed are lock-based protocols using techniques like two-phase locking, and timestamp-based protocols.
The document discusses transaction processing and ACID properties in databases. It defines a transaction as a group of tasks that must be atomic, consistent, isolated, and durable. It provides examples of transactions involving bank account transfers. It explains the four ACID properties - atomicity, consistency, isolation, and durability. It also discusses transaction states, recovery, concurrency control techniques like two-phase locking and timestamps to prevent deadlocks.
This document discusses transaction concepts and properties in database systems. It covers:
- Transactions access and possibly update data items as a unit of execution.
- ACID properties that transactions must satisfy: Atomicity, Consistency, Isolation, and Durability.
- Serializability is required for concurrent transaction executions to be equivalent to a serial execution and preserve consistency.
- Concurrency control schemes ensure transactions are isolated and serializability is enforced.
1. Concurrency control and recovery in distributed databases faces additional problems compared to centralized databases such as dealing with multiple copies of data, site failures, and distributed transactions.
2. There are several techniques for concurrency control in distributed databases including designating a primary site for locking coordination, distributing the locking load across multiple primary copy sites, and using timestamps to order transactions.
3. Recovery from coordinator failures requires electing a new coordinator - either restarting transactions, using a backup site, or electing a new site via consensus.
The document discusses transactions in database management systems and the ACID properties that transactions must satisfy. It describes the four ACID properties - atomicity, consistency, isolation, and durability. Atomicity ensures that transactions are treated as an atomic unit and either fully occur or not at all. Consistency requires that transactions alone preserve the consistency of the database. Isolation ensures that concurrently executing transactions are isolated from each other. Durability means the effects of committed transactions persist even if the system crashes. The document also discusses transaction schedules, concurrency control, and anomalies that can occur with concurrent transaction execution.
Delusional Disorders
Pakistani hought Processes
BACKGROUND
The client is a 34-year-old Pakistani female who moved to the United States in her late teens/early 20s. She is currently in an “arranged” marriage (her husband was selected for her since she was 9 years old). She presents to your office today following a 21 day hospitalization for what was diagnosed as “brief psychotic disorder.” She was given this diagnosis as her symptoms have persisted for less than 1 month.
Prior to admission, she was reporting visions of Allah, and over the course of a week, she believed that she was the prophet Mohammad. She believed that she would deliver the world from sin. Her husband became concerned about her behavior to the point that he was afraid of leaving their 4 children with her. One evening, she was “out of control” which resulted in his calling the police and her subsequent admission to an inpatient psych unit.
During today’s assessment, she appears quite calm, and insists that the entire incident was “blown out of proportion.” She denies that she believed herself to be the prophet Mohammad and states that her husband was just out to get her because he never loved her and wanted an “American wife” instead of her. She tells you that she knows this because the television is telling her so.
She currently weighs 140 lbs, and is 5’ 5”
SUBJECTIVE
Client reports that her mood is “good.” She denies auditory/visual hallucinations, but believes that the television does talk to her. She believes that Allah sends her messages through the TV. At times throughout the clinical interview, she becomes hostile towards the PMHNP, but then calms down.
You reviewed her hospital records and find that she has been medically worked up by a physician who reported her to be in overall good health. Lab studies were all within normal limits.
Client admits that she stopped taking her Risperdal about a week after she got out of the hospital because she thinks her husband is going to poison her so that he can marry an American woman.
MENTAL STATUS EXAM
The client is alert, oriented to person, place, time, and event. She is dressed appropriately for the weather and time of year. She demonstrates no noteworthy mannerisms, gestures, or tics. Her speech is slow and at times, interrupted by periods of silence. Self-reported mood is euthymic. Affect constricted. Although the client denies visual or auditory hallucinations, she appears to be “listening” to something. Delusional and paranoid thought processes as described, above. Insight and judgment are impaired. She is currently denying suicidal or homicidal ideation.
The PMHNP administers the PANSS which reveals the following scores:
-40 for the positive symptoms scale
-20 for the negative symptom scale
-60 for general psychopathology scale
Diagnosis: Schizophrenia, paranoid type
RESOURCES
§ Kay, S. R., Fiszbein, A., & Opler, L. A. (1987). The Positive and Negative Syndrome Scale (PANSS) for schizophrenia. Schizophrenia Bulleti.
The document discusses concurrency control in database management systems. It defines key terms like transaction, atomicity, consistency, isolation, and durability. Transactions must have ACID properties - Atomicity, Consistency, Isolation, and Durability. Atomicity means all operations of a transaction are completed or none are. Consistency means the database remains consistent before and after a transaction. Isolation means transactions appear to execute serially despite concurrent execution. Durability means committed transactions persist even after failures.
1. Transaction Processing and Concurrency Control.pptxcalf_ville86
This document discusses transaction processing and concurrency control in database systems. It covers topics such as transactions and their properties including atomicity, consistency, isolation, and durability. It also discusses concurrency control and how locking methods work to ensure serializability by coordinating concurrent transactions through the use of locks at different levels of granularity like the database, table, page, and row levels. The scheduler establishes the execution order of operations for concurrent transactions.
This document discusses concurrency control and its protocols. Concurrency control ensures correct results from concurrent operations while maximizing performance. It addresses issues that can arise from multiple transactions executing simultaneously on the same data. The ACID rules of atomicity, consistency, isolation, and durability are explained. Common concurrency control protocols include lock-based, two phase locking, and timestamp-based protocols. Lock-based protocols use shared and exclusive locks to control access to data. Two phase locking follows a growing and shrinking phase approach. Timestamp-based protocols serialize transactions based on timestamps.
Concurrency control ensures that operations from concurrent processes generate correct results while maximizing performance. It maintains consistency when components interacting concurrently could violate one another's consistency rules. In databases, concurrency control guarantees transactions are serializable and follow the ACID properties of atomicity, consistency, isolation, and durability. Mechanisms include optimistic, pessimistic, and semi-optimistic approaches, with the goal of generating serializable schedules for concurrency and recoverability.
The document discusses transaction management in EJB. It defines transactions and the ACID properties of atomicity, consistency, isolation, and durability. It describes transaction models like flat and nested transactions. It also discusses transaction isolation levels, distributed transactions using two-phase commit protocol, and how to control transactions programmatically using the Java Transaction API in EJB.
This document discusses transaction management in SQL. It defines a transaction as a logical unit of work that must fully commit or roll back. Transactions ensure data integrity by allowing all or none of a set of SQL statements to apply. The document covers transaction outcomes, the need for transactions, locking, isolation levels, deadlocks, and how to control transactions using SQL statements.
The document discusses transactions and the ACID properties that must be ensured to maintain data integrity in a database system. It defines a transaction, provides an example of a funds transfer transaction, and explains the goals of atomicity, consistency, isolation, and durability. It discusses issues that can arise from concurrent transaction execution like inconsistent views of data and lost updates. Mechanisms like concurrency control and locking are used to preserve the ACID properties when transactions run concurrently.
1 ) a transaction is a logical unit of work each transaction is sequ.pdfkareemangels
1 ) a transaction is a logical unit of work each transaction is sequence of logical related
commands that acomplish one task and transforms the database from one consistent state into
another .transactions are atomic in other words sysbase iq executes all the statements within the
transaction as unit at the end of each transaction changes can be commited to make them
permanent for any reason if transactions do not process properly then some or all other
intermediate changes can be undone or rolled back and the user application controls under which
the changes are commited or rolled back .
4) transaction has four properties ie atomicity ,consistency , isolation and durability ie atomicity -
requires that all parts of transaction must be completed or transactions is aborted and this
property ensures that the database remains in a consistent state
consistency- indicates the permenance of database in the consistency state .
isolation - means that the data required by an executing transaction cannot be accessed by any
other transactions until the first transaction finishes this propert ensures the data consistency for
concurrently executing transactions.
durability - indicates that the database will be in permanent consistent state after the execution of
transaction
5) serialiazability- means that the series of concurrent transactions will yield the same result as if
they were executed one after another .
2) consistent databse state is one in which all data integrity constraints are satisfied to achieve a
consistence database state a transaction must take the database from one consistent state to
another .
3) the databse is designed to verify the syntactic accuracy of the database commands given by
the user to be executed by the dbms the dbms will check the database exists that the referenced
attributes exists in the selected tables , that the attribute data type are correct and so on
unfortunately the dbms is not designed to guarantee that the syntacticaly correct transaction
actually represent the real world events .
6) transaction log is a special dbms table that contains description of all the database transactions
executed by the dbms . the database transaction log plays a crucial role in maintaining database
concurrency control and integrity .the information stored in the log is used by the dbms to
recover the database after the transaction is aborted or after system failure the transaction log is
stored in different hard disks or in different media tape to prevent the failure caused by a media
error .
7) the scheduler is the dbms concept that establish the order in which concurrent database
operations are executed . the schedular interleaves the execution of the database operations to
ensure the serialiazability of transactions in other woords the schedular guarantees that the
execution of concurrent transactions will yield the same results as though the transactions were
executed one after the another .the scheduler is important because it.
This document discusses concurrency control algorithms for distributed database systems. It describes distributed two-phase locking (2PL), wound-wait, basic timestamp ordering, and distributed optimistic concurrency control algorithms. For distributed 2PL, transactions lock data items in a growing phase and release locks in a shrinking phase. Wound-wait prevents deadlocks by aborting younger transactions that wait on older ones. Basic timestamp ordering orders transactions based on their timestamps to ensure serializability. The distributed optimistic approach allows transactions to read and write freely until commit, when certification checks for conflicts. Maintaining consistency across distributed copies is important for concurrency control algorithms.
Transactions and Concurrency Control in distributed systems. Transaction properties, classification, and transaction implementation. Flat, Nested, and Distributed transactions. Inconsistent Retrievals, Lost Update, Dirty Read, and Premature Writes Problem
This document provides an overview of database transactions. It defines transactions and discusses their key concepts and states. It describes ACID properties including atomicity, consistency, isolation, and durability. It discusses implementation of atomicity and durability using shadow databases. It also covers concurrent execution, serializability, recoverability, and how transactions are defined in SQL.
The document discusses transaction processing and recovery and concurrency control in database systems. It defines a transaction as a logical unit of work that takes a database from one consistent state to another. Transactions must have the ACID properties of atomicity, consistency, isolation, and durability. Concurrency control techniques ensure transactions execute correctly and isolation despite running concurrently. Recovery techniques such as logging and checkpoints allow recovering the database to a consistent state if a failure occurs during transaction processing.
This document discusses transaction management and concurrency control in databases. It defines a transaction as a logical unit of work that must be entirely completed or aborted, with no partial states. Transactions have properties of atomicity, consistency, isolation, and durability. The document uses an example of a sales transaction to illustrate transactions and explains how the database transaction log tracks transactions to support recovery.
The document discusses concurrency control in database management systems. Concurrency control ensures that transactions are performed concurrently without conflicting results by using methods like locking and timestamps. It prevents issues like lost updates, dirty reads, and non-repeatable reads. The main concurrency control protocols discussed are lock-based protocols using techniques like two-phase locking, and timestamp-based protocols.
The document discusses transaction processing and ACID properties in databases. It defines a transaction as a group of tasks that must be atomic, consistent, isolated, and durable. It provides examples of transactions involving bank account transfers. It explains the four ACID properties - atomicity, consistency, isolation, and durability. It also discusses transaction states, recovery, concurrency control techniques like two-phase locking and timestamps to prevent deadlocks.
This document discusses transaction concepts and properties in database systems. It covers:
- Transactions access and possibly update data items as a unit of execution.
- ACID properties that transactions must satisfy: Atomicity, Consistency, Isolation, and Durability.
- Serializability is required for concurrent transaction executions to be equivalent to a serial execution and preserve consistency.
- Concurrency control schemes ensure transactions are isolated and serializability is enforced.
1. Concurrency control and recovery in distributed databases faces additional problems compared to centralized databases such as dealing with multiple copies of data, site failures, and distributed transactions.
2. There are several techniques for concurrency control in distributed databases including designating a primary site for locking coordination, distributing the locking load across multiple primary copy sites, and using timestamps to order transactions.
3. Recovery from coordinator failures requires electing a new coordinator - either restarting transactions, using a backup site, or electing a new site via consensus.
The document discusses transactions in database management systems and the ACID properties that transactions must satisfy. It describes the four ACID properties - atomicity, consistency, isolation, and durability. Atomicity ensures that transactions are treated as an atomic unit and either fully occur or not at all. Consistency requires that transactions alone preserve the consistency of the database. Isolation ensures that concurrently executing transactions are isolated from each other. Durability means the effects of committed transactions persist even if the system crashes. The document also discusses transaction schedules, concurrency control, and anomalies that can occur with concurrent transaction execution.
Similar to DBF-Lecture11-Chapter12.pptDatabase Principles Fundam.docx (20)
Delusional Disorders
Pakistani hought Processes
BACKGROUND
The client is a 34-year-old Pakistani female who moved to the United States in her late teens/early 20s. She is currently in an “arranged” marriage (her husband was selected for her since she was 9 years old). She presents to your office today following a 21 day hospitalization for what was diagnosed as “brief psychotic disorder.” She was given this diagnosis as her symptoms have persisted for less than 1 month.
Prior to admission, she was reporting visions of Allah, and over the course of a week, she believed that she was the prophet Mohammad. She believed that she would deliver the world from sin. Her husband became concerned about her behavior to the point that he was afraid of leaving their 4 children with her. One evening, she was “out of control” which resulted in his calling the police and her subsequent admission to an inpatient psych unit.
During today’s assessment, she appears quite calm, and insists that the entire incident was “blown out of proportion.” She denies that she believed herself to be the prophet Mohammad and states that her husband was just out to get her because he never loved her and wanted an “American wife” instead of her. She tells you that she knows this because the television is telling her so.
She currently weighs 140 lbs, and is 5’ 5”
SUBJECTIVE
Client reports that her mood is “good.” She denies auditory/visual hallucinations, but believes that the television does talk to her. She believes that Allah sends her messages through the TV. At times throughout the clinical interview, she becomes hostile towards the PMHNP, but then calms down.
You reviewed her hospital records and find that she has been medically worked up by a physician who reported her to be in overall good health. Lab studies were all within normal limits.
Client admits that she stopped taking her Risperdal about a week after she got out of the hospital because she thinks her husband is going to poison her so that he can marry an American woman.
MENTAL STATUS EXAM
The client is alert, oriented to person, place, time, and event. She is dressed appropriately for the weather and time of year. She demonstrates no noteworthy mannerisms, gestures, or tics. Her speech is slow and at times, interrupted by periods of silence. Self-reported mood is euthymic. Affect constricted. Although the client denies visual or auditory hallucinations, she appears to be “listening” to something. Delusional and paranoid thought processes as described, above. Insight and judgment are impaired. She is currently denying suicidal or homicidal ideation.
The PMHNP administers the PANSS which reveals the following scores:
-40 for the positive symptoms scale
-20 for the negative symptom scale
-60 for general psychopathology scale
Diagnosis: Schizophrenia, paranoid type
RESOURCES
§ Kay, S. R., Fiszbein, A., & Opler, L. A. (1987). The Positive and Negative Syndrome Scale (PANSS) for schizophrenia. Schizophrenia Bulleti.
Deloitte’s 2020 Global Blockchain SurveyFrom promise to re.docxrandyburney60861
Deloitte’s 2020 Global
Blockchain Survey
From promise to reality
DELOITTE BLOCKCHAIN
At Deloitte, our people collaborate globally with clients, regulators, and policymakers on how
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https://www2.deloitte.com/us/en/pages/consulting/solutions/blockchain-solutions-and-services.html
Introduction: The evolution of blockchain 2
A more “real” reality for blockchain 4
Digital assets today and tomorrow 9
Cybersecurity 13
Global digital identity 15
Regulatory considerations 17
Governance in blockchain consortia 19
Regional analysis 21
Concluding thoughts: The road taken 24
Appendix 25
Endnotes 36
Contents
2
Introduction: The
evolution of blockchain
MORE THAN A decade has passed since the introduction of what we know today as blockchain technology. Over that time,
the promise of what the technology could offer
businesses and industries has evolved from a
cryptocurrency payment platform to something
bigger, game-changing, and truly disruptive. In
recent years, we have seen sentiment about
blockchain’s potential similarly evolving, along
with companies directing actual investment
dollars toward applications.
In Deloitte’s 2019 Global Blockchain Survey,
we observed this continuing trend in thinking
and investment, even if some vestiges of doubt
and old-school thinking remained about the
technology’s promise.1 This year’s survey
suggests that those doubts are fading further,
and that blockchain is solidly entrenched in
the strategic thinking of organizations across
industries, sectors, and applications.
There are more substantive examples in
the marketplace of how both startups and
mature businesses are deploying blockchain.
Organizations appear to be more committed than
ever to blockchain and are demonstrating this by
implementing it as part of their normal course
of business.
That’s the key takeaway from our 2020 Global
Blockchain Survey, which finds that leaders no
longer consider the technology groundbreaking
and merely promising—they now see it as integral
to organizational innovation. This year, the C-suite
is putting money and resources behind blockchain
as a strategic solution in more meaningful and
tangible ways—in projects big and not so big—
putting i.
DELL COMPANY’ Application of the accounting theories on the comp.docxrandyburney60861
DELL COMPANY’
Application of the accounting theories on the company
-stakeholder theory
-shareholder theory
-conceptual framework of a company
• Purpose
• Example
Topic: Sustainability Reporting in Accounting
Task details: Research the current state of Sustainability Reporting, including the issues, practices etc. using higher order analysis and explaining the implications for various stakeholders in relation to financial decision making.
Report: 1500 wordsexcluding the references ; executive summary, table of contents, appropriate headings and subheadings, recommendations/ findings/ conclusions, in-text referencing and reference list( Harvard -anglia style)
Assessment Type: Group report– combined group and individual assessment task.
Purpose: This assessment is designed to allow students to research and analyse current social issues in accounting and evaluate their impact on various stakeholders. As a group assessment, it further develops students’ team working s******s
Value: Total value is 30% made up of 10% Group marks for report plus 20% individual marks for presentation. This assignment marks will be scaled to a mark out of 30 total subject marks.
Topic: Sustainability Reporting in Accounting
Task Details: Groups are to research the current state of Sustainability Reporting. As a result of their research groups detailing the current state of sustainability reporting including the issues, practices, etc using higher order analysis and explaining the implications for various stakeholders in relation to financial decision making. The report should conclude with supported specific recommendations as to how organisations and their accounting advisors should proceed in light of the analysis.
Research requirements: Students need to support their analysis with reference from the text and minimum of ten (10) suitable, reliable, current and academically acceptable sources – check with your tutor if unsure of the validity of sources. Groups seeking Credit or above grades should support their analysis with increased number of reference sources comparable to the grade they are seeking.
Group Report 1500 + 10% word report format – Word .doc or .docx. Title page, executive summary, table of contents, appropriate headings and sub-headings, recommendations/findings/conclusions, in-text referencing and reference list (Harvard – Anglia style), attachments if relevant. Single spaced, font Times New Roman 12pt, Calibri 11pt or Arial 10pt.
Additional details:
DELL COMPANY
• Fina******** cost**************** cost*********** cost ********wcase the benefit equally
• Corporate culture
• Look at bigger perspective
• Showing impacts: shareholders, academic, media etc
• Directors release reports
• Capital market research
• AMP general meeting
• Showvcase the good and bad of the DELL COMPANY:ACCOUNTING ISSUES
.
Deliverable Length10–15 slides not including title and refere.docxrandyburney60861
Deliverable Length:
10–15 slides not including title and reference slides with 150-200 words speaker notes
OBJECTIVES
Create a PowerPoint presentation with speaker notes to educate others regarding the development of an operational budget and a capital budget. Be sure to include the following:
Provide the process for developing an operational budget.
Provide the process for developing a capital budget.
Differentiate between the operational and capital budgets.
Explain how the capital budget is required for strategic management.
Please submit your assignment.
.
Deliverable 6 - Using Business VisualsCompetencyExamine and de.docxrandyburney60861
Deliverable 6 - Using Business Visuals
Competency
Examine and design visual media communication to produce effective business materials.
Scenario
You are a website designer and are currently being considered as the designer for a complete redesign of a medical facility's website page. They have not updated their website in over 15 years due to the lack of staff. The website needs the redesign to target the specific visual preferences of patients and medical clients. They have several other designers that they are interviewing, and you decide to create a video presentation to impress them to choose you as their website designer.
As you begin your presentation, you decide that your design will include the following visual concepts and elements:
1. Visual Organization
2. Visual Simplicity
3. Visual Interactivity
4. Charts and Graphs
5. Images
In designing these visual elements, you keep the target audience of patients and medical clients as the main focus. You carefully consider what these types of people wish to see at a medical facility. You also consider what visual elements will attract the eye, and yet enhance a specific mood and emotional response for viewers.
After creating the website, you record your explanation of your visual design choices in an audio/video screen share.
Your presentation should be a maximum of 5 minutes.
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Deliverable 5 - Proposed HR Initiatives Presentation
Assignment Content
Competency
Assess the impact of Human Resources practices on the success of the organization and its human capital.
Student Success Criteria
View the grading rubric for this deliverable by selecting the “This item is graded with a rubric” link, which is located in the
Details & Information
pane.
Scenario
The CEO of a technology-services B2B company has just announced a momentous change in its strategic direction. He wants to begin offering full turn-key technology facilities to customers instead of just offering additional technology solutions to customers’ existing facilities. This change will require many new employees with different knowledge, skills, and abilities than the current workforce. It will also require dramatically different approaches to marketing and sales. The HR Director asks you to help develop a proposal for a strategic HR plan to deal with the change and present it to the top leadership.
The plan will support the change by proposing HR initiatives related to:
Talent acquisition (new employees)
Talent development (current employees)
Instructions
Create a
presentation, with speaker’s notes
, that:
Describes at least one proposed initiative for each: talent acquisition and talent development.
Identifies metrics to be used to measure the success of initiatives.
Describes a realistic and effective data collection plan for the metrics you selected.
Identifies potential ethical issues and/or risks related to the proposed data collection plan.
Provides a risk mitigation plan as needed.
Details how each initiative would impact the business objectives of the organization.
Provides attribution for credible sources used in the presentation.
.
Deliverable 4 - Diversity and Inclusion PolicyAssignment Con.docxrandyburney60861
Deliverable 4 - Diversity and Inclusion Policy
Assignment Content
Competency
Create policies and procedures that manage risk, are legally compliant, and align to organizational strategy.
Student Success Criteria
View the grading rubric for this deliverable by selecting the “This item is graded with a rubric” link, which is located in the
Details & Information
pane.
Scenario
You are the HR Director of a 3-star hotel chain that has locations throughout the United States. In a review of last year’s recruitment, selection, and hiring data, you realize that these HR practices have not resulted in the level of employee diversity desired by the CEO. Currently, there is no formal diversity and inclusion policy for the organization. Therefore, you propose that a new policy document be written and communicated to all employees, as well as be incorporated into all training programs for those involved in the recruitment and selection processes. The CEO agrees with your proposal.
Instructions
Create a
diversity and inclusion policy
that:
Details the policy objective and scope.
Explains the difference between diversity and inclusion.
Outlines initiatives to promote diversity and inclusion throughout the organization.
Includes instructions for employees to follow if they feel they have been subjected to any treatment that is in violation of the policy and/or listed initiatives promoting diversity and inclusion.
Provides attribution for credible sources used in the policy.
.
Deliverable 4 - Global Environment ChallengesCompetencyC.docxrandyburney60861
Deliverable 4 - Global Environment Challenges
Competency
Create solutions for organizational and leadership challenges in a global environment.
Scenario
You are the HR Training and Development Manager at Lots of Stuff International, a global company. The company has offices around the globe, which requires employees to work with peers in multiple countries in cross-functional and cross-global teams. The company has recently conducted an employee engagement survey across all areas of the company. The results indicate a lack of engagement and satisfaction of employees who work in these global-cross functional teams. Upon investigation, you discover that employees indicate dissatisfaction with a lack of community and social interaction in their teams. They indicate this may be a function of culture and religious differences, time zone differences, or work ethic differences. This has led employees to be less invested in working together. The CEO, Ms. Amelia Rienhardt, has tasked you with creating a plan to develop community within these teams across the global workforce, with the end goal of enhancing engagement and satisfaction. This plan will be unveiled to all teams in a company-wide presentation.
Instructions
Create a presentation, including speaker notes, presenting your global employee engagement plan. The presentation should:
Assess factors that may lead to a lack of employee engagement and satisfaction in working in global cross-functional teams.
Address each identified factor from your assessment:
Cultural differences
Religious differences
Time zone differences
Work ethic differences
Recommend a process to develop communication channels in diverse teams.
Provide counsel on dealing with cross-cultural conflict.
Develop a strategy for ongoing cross-cultural team building.
Identify ideas for enhancing social interactions between cross-cultural work teams.
Include a plan for the use of technology for employee engagement and social interaction.
Be sure to provide proper attribution for credible sources used in the presentation.
.
Deliverable 03 - Humanities (Test-Out Sophia Replacement)
Competency
Formulate, express, and support individual perspectives on diverse works and issues.
Instructions
You will act as a critic for some of the main subjects covered in the humanities. You will conduct a series of short, evaluative critiques of film, philosophy, literature, music, and myth. You will respond to five different prompts, and each response should include an analysis of the topics using terminology unique to that subject area and should include an evaluation as to why the topic stands the test of time. The five prompts are as follows:
Choose a film and offer an analysis of why it is an important film, and discuss it in terms of film as art. Your response should be more than a summary of the film.
Imagine you had known Plato and Aristotle and you had a conversation about how we
fall in love
. Provide an overview of how Plato would explain falling in love, and then provide an overview of how Aristotle might explain falling in love.
Compare and contrast the two poems below:
LOVE’S INCONSISTENCY
I find no peace, and all my war is done;
I fear and hope, I burn and freeze likewise
I fly above the wind, yet cannot rise;
And nought I have, yet all the world I seize on;
That looseth, nor locketh, holdeth me in prison, And holds me not, yet can I ’scape no wise;
Nor lets me live, nor die, at my devise,
And yet of death it giveth none occasion.
Without eyes I see, and without tongue I plain;
I wish to perish, yet I ask for health;
I love another, and yet I hate myself;
I feed in sorrow, and laugh in all my pain;
Lo, thus displeaseth me both death and life,
And my delight is causer of my grief.
Petrarch
After great pain a formal feeling comes—
The nerves sit ceremonious like tombs;
The stiff Heart questions—was it He that bore?
And yesterday—or centuries before?
The feet mechanical go round
A wooden way
Of ground or air or ought
Regardless grown,
A quartz contentment like a stone.
This is the hour of lead
Remembered if outlived
As freezing persons recollect
The snow—
First chill, then stupor, then
The letting go
Emily Dickinson
4. Compare and contrast these two pieces of music:
Beethoven’s Violin Romance No. 2
Scott Joplin’s Maple Leaf Rag
5.Explain in classical terms why a modern character is a hero. Choose from either Luke Skywalker, Indiana Jones, Bilbo Baggins, Harry Potter, Katniss Everdeen, or Ender Wiggins.
Grading Rubric
0
1
2
3
4
Category
Not Submitted
No pass
Competence
Proficiency
Mastery
Analysis
Not Submitted
Provides an explanation of the topic but doesn't use terminology common to the subject.
Provides an explanation of the topic using terminology common to the subject.
Provides a detailed explanation of the topic using terminology common to the subject.
Explains in great detail the topic using terminology common to the subject and references other ideas/works in that subject.
Evaluation
Not Submit.
The document provides instructions for a humanities assessment that requires critiquing and analyzing various topics through short responses. The assessment includes five prompts requiring analysis of a film as art, a discussion of how Plato and Aristotle would explain falling in love, a comparison of two poems, a comparison of two pieces of music, and an explanation of why a modern character exemplifies classical heroism. For each prompt, the response must include terminology specific to the subject area and an evaluation of why the topic stands the test of time.
DEFINITION a brief definition of the key term followed by t.docxrandyburney60861
DEFINITION
:
a brief definition of the key term followed by the APA reference for the term; this does not count in the word requirement.
SUMMARY
:
Summarize the article in your own words- this should be in the 150-200 word range. Be sure to note the article's author, note their credentials and why we should put any weight behind his/her opinions, research or findings regarding the key term.
ANALYSIS
:
Using 300-350 words, write a brief analysis, in your own words of how the article relates to the selected chapter Key Term. An analysis is not rehashing what was already stated in the article, but the opportunity for you to add value by sharing your experiences, thoughts and opinions. This is the most important part of the assignment.
REFERENCES
:
All references must be listed at the bottom of the submission--in APA format.
Be sure to use the headers in your submission to ensure that all aspects of the assignment are completed as required.
DiSCUSSION:
Describe social bandwidth and share an experience you’ve had with this concept within your previous interactions.
.
Definition of HIVAIDS. What are the symptoms and general characteri.docxrandyburney60861
Definition of HIV/AIDS. What are the symptoms and general characteristics of HIV/AIDS
What is the best way to bring awareness to AIDS in the school system.
Detailed explanation of a classroom activity, instructional technique, or program that can be utilized at a school to help a student with HIV/AIDS.
Use a minimum of three (3) resources including peer reviewed articles.
Use APA format.
.
Definition of Ethos and How to Use it1. Trustworthiness Does y.docxrandyburney60861
Definition of Ethos and How to Use it
1. Trustworthiness Does your audience believe you are a good person who can be trusted to tell the truth?
2. Similarity Does the writer try to get the reader to identify with him or her? This can be done through language
3. Authority Does the writer have formal or informal authority? Does the writer try to relate to the reader?
4. Reputation What are the expertise the writer uses? How many does he use? What are their areas of authority?
Logos: Logical reasoning, which has two bases:
Deductive reasoning, and
Inductive reasoning
Deductive Reasoning
Deductive reasoning generally start with one or more premises, and then comes to a conclusion from them. Premises can be facts, claims, evidence, or a previously proven conclusion. The key is that in a deductive argument, if the writer’s premises are true, then the conclusion must be true.
1. Education determines one’s class base.
2. One’s class base will shape one’s employment.
3. Therefore, education will determine one’s employment.
Inductive Reasoning
Inductive reasoning is similar in that it consists of premises, which lead to a conclusion. The difference is that the conclusion is not guaranteed to be true — we can only state it with some degree of confidence.
For example, consider the following inductive argument:
5. All Six Minutes articles you have read in the past were insightful. (premise)
6. This is a Six Minutes article. (premise)
Therefore, this article is insightful. (conclusion)
How to Identify Logos
Make it Understandable: Does the writer make the argument understandable? What tools does he or she use to do this?
Make it Logical: Does the arguments make sense? Or does the writer require the reader to make an extreme leap of faith? How easy is it for the writer to make a connection to the argument?
Make it Real: Does the writer make the argument real? Is the argument concrete or abstract?
The language plain language: Does the writer use technical jargon or is a portion of language used for a specific reader that isn’t familiar with the reader?
Does the writer use short words and phrases over long and convoluted counterparts?
The language is explicit: Does the writer make his or her argument plain? What techniques does he or she use to establish explicit argument?
The writer uses a couple premises, to establish his or her position? Are they relatable? Do they show relationship between them? “And these five advantages — capital costs, scheduling, inventory control, marketing, and employee satisfaction — together make this a winning proposal.”
Trace sequences or processes in order.
Does the writer jump around to different places or is there an order to his or her steps that create clarity or confusion for the reader?
Use comparisons, analogies, and metaphors.
Does the writer introduce new concepts, with an appropriate analogy which helps the audience understand the new concept in terms of how they already understand the old one?.
Definition Multimodal refers to works that use a combination .docxrandyburney60861
Definition:
Multimodal refers to works that use a combination of
modes
, including words, static images, moving images, and sounds.
Examples:
Works include print advertisements, commercials, videos, websites.
Assignment:
Write a summary-analysis paper on a multimodal advertisement.
Methods of critique
: Propaganda Techniques
Length:
2-3 pages (summary intro, two bodies, conclusion)
.
Definition Argument Essay AssignmentGoal Write a 1,500.docxrandyburney60861
Definition Argument Essay Assignment
Goal
Write a 1,500-1,750-word essay using five to seven academic resources in which you argue that a contested “case” involving the sale, trade, or donation of human organs fits (or does not fit) within a given category. A case may include a specific news article, story, or incident illustrating a dilemma or controversy relating to the exchange of human organs. The case does not need to be a court case.
Directions
Follow these steps when composing your essay:
1. Start by selecting a controversial case found in the media involving the sale, trade, or donation of human organs. For example, an appropriate case might include a story in the news about an organ broker, and the term to define might be “criminal.”
2. Decide what category you think your case belongs in, with the understanding that others may disagree with you about the definition of your category, and/or whether your chosen case matches your category.
3. In the opening of your essay, introduce the case you will examine and pose your definition question. Do not simply summarize here. Instead, introduce the issue and offer context.
4. To support your argument, define the boundaries of your category (criteria) by using a commonly used definition or by developing your own extended definition. Defining your boundaries simply means naming the criteria by which you will discuss your chosen case involving the sale, trade, or donation of human organs. If you determine, for example, that an organ broker is a criminal, what criteria constitute this? A criminal may intentionally harm others, which could be one of your criteria.
5. In the second part of your argument (the match), show how your case meets (or does not meet) your definition criteria. Perhaps by comparing or sizing up your controversial case to other cases can help you to develop your argument.
This essay is NOT simply a persuasive essay on the sale, trade, or donation of human organs. It is an argumentative essay where the writer explains what a term means and uses a specific case to explore the meaning of that term in depth.
First Draft Grading
· You will receive completion points for the first draft based upon the successful submission of a complete draft.
· Because your first draft is a completion grade, do not assume that this grade reflects or predicts the final grade. If you do not consider your instructor’s comments, you may be deducted points on your final draft.
Final Draft Grading
The essay will be graded using a rubric. Please review the rubric prior to beginning the assignment to become familiar with the assignment criteria and expectations.
Sources
· Include in-text citations and a references page in GCU Style for FIVE to SEVEN scholarly sources outside of class texts.
· These sources should be used to support any claims you make and should be present in the text of the essay.
· Use the GCU Library to help you find sources.
· Include this research in the paper i.
DEFINITION a brief definition of the key term followed by the APA r.docxrandyburney60861
DEFINITION: a brief definition of the key term followed by the APA reference for the term; this does not count in the word requirement.
SUMMARY: Summarize the article in your own words- this should be in the 150-200-word range. Be sure to note the article's author, note their credentials and why we should put any weight behind his/her opinions, research or findings regarding the key term.
DISCUSSION: Using 300-350 words, write a brief discussion, in your own words of how the article relates to the selected chapter Key Term. A discussion is not rehashing what was already stated in the article, but the opportunity for you to add value by sharing your experiences, thoughts and opinions. This is the mostimportant part of the assignment.
REFERENCES: All references must be listed at the bottom of the submission--in APA format. (continued) Be sure to use the headers in your submission to ensure that all aspects of the assignment are completed as required.
.
Defining Privacy in Employee Health ScreeningCases Ethical .docxrandyburney60861
Defining Privacy in Employee Health Screening
Cases: Ethical Ramifications Concerning
the Employee/Employer Relationship
V
Michele Simms
ABSTRACT. Issues of privacy and employee health screen-
ing rank as two of the most important ethical concerns
organizations will face in the next five years. Despite the
increasing numbers of social scientists researching personal
privacy and the current focus on workplace privacy rights as
one of the most dynamic areas of employment law, the
concept of privacy remains relatively ahstract. Understand-
ing how the courts defme privacy and use the expectation of
privacy standards is paramount given the strategic impor-
tance of the law as a legal socializing agent. This article
reports on two federal court decisions involving employer
drug and HIV testing whose determinations relied on
assumptions about the psychological dimensions of privacy.
How the courts define privacy, the outcome of this defini-
tion and the ethical ramifications as it affects the employee/
employer relationship are discussed.
Introduction
Each year American companies require employees to
submit to millions of blood and urine tests, x-rays,
and other medical and laboratory procedures. "In
fact, with the exception of typing and similar skills
tests for office and clerical employees, medical
screening is the most widely used pre-employment
test in all major employment categories" (BNA,
1987). It is predicted that in the next five years
testing will become a standard requirement when
applying for employment and/or health and life
insurance (Rothstein, 1989).
Michele Simms, as an adjunct professor of business communication
and organizational behavior, has taught at the University of
Michigan, Wayne State University and Oakland University
schools of business in Michigan. In addition to teaching, she
consults in the areas of worksite wellness, alternative dispute
resolution, transition management and change.
One factor contributing to the increase in em-
ployee health screening is the development of drug
abuse and AIDS as socially compelling public health
concerns (Falco and Cikins, 1989) that are costly to
employers, thus leading to an increase and/or initia-
tion of drug and HIV testing in both private and
public sector employment. One concern associated
with health screening is the issue of privacy and the
parallel communication activity of self-disclosure
that is used to express and maintain privacy states.
The issues of privacy and testing involve the
fundamental conflict of ethical principles between
individual rights and public safety needs and are the
subject today of increasing legislative and judicial
activity. A peripheral ethical concern that has not
been addressed but of equal importance is whether
the psychological dimensions of privacy are ac-
knowledged in court decisions involving employer
health screening practices. Traditionally lawyers and
judges Htigate and decide cases based upon principles
of legal positivi.
Define diversity” and inclusion” as applied to your pre.docxrandyburney60861
Define “diversity” and “inclusion” as applied to your presentation that will compare two healthcare organizations. Describe the two healthcare organizations you are comparing, including type and degree of diversity and inclusion, as well as organization type, size, location, and other distinguishing factors. Include supporting sources.
Analyze the culture of the two healthcare organizations and how each is influenced by diversity and inclusion.
Compare the cultures of the two healthcare organizations based on the role of diversity and inclusion in each, and strengths and weaknesses that relate to or derive from the degree of diversity and inclusion.
Summarize your conclusions on the impact of diversity and inclusion on organizational culture in healthcare settings based on your comparison.
Apply leadership strategies for a nurse executive to promote greater diversity, retain diverse staff members, and build cohesive teams and work groups.
.
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
Philippine Edukasyong Pantahanan at Pangkabuhayan (EPP) CurriculumMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 𝟏)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐄𝐏𝐏 𝐂𝐮𝐫𝐫𝐢𝐜𝐮𝐥𝐮𝐦 𝐢𝐧 𝐭𝐡𝐞 𝐏𝐡𝐢𝐥𝐢𝐩𝐩𝐢𝐧𝐞𝐬:
- Understand the goals and objectives of the Edukasyong Pantahanan at Pangkabuhayan (EPP) curriculum, recognizing its importance in fostering practical life skills and values among students. Students will also be able to identify the key components and subjects covered, such as agriculture, home economics, industrial arts, and information and communication technology.
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐍𝐚𝐭𝐮𝐫𝐞 𝐚𝐧𝐝 𝐒𝐜𝐨𝐩𝐞 𝐨𝐟 𝐚𝐧 𝐄𝐧𝐭𝐫𝐞𝐩𝐫𝐞𝐧𝐞𝐮𝐫:
-Define entrepreneurship, distinguishing it from general business activities by emphasizing its focus on innovation, risk-taking, and value creation. Students will describe the characteristics and traits of successful entrepreneurs, including their roles and responsibilities, and discuss the broader economic and social impacts of entrepreneurial activities on both local and global scales.
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How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
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A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
Communicating effectively and consistently with students can help them feel at ease during their learning experience and provide the instructor with a communication trail to track the course's progress. This workshop will take you through constructing an engaging course container to facilitate effective communication.
1. DBF-Lecture11-Chapter12.ppt
Database Principles: Fundamentals of Design, Implementations
and Management
Lecture11- CHAPTER 12: Transaction Management and
Concurrency Control
Presented by Rabia Cherouk
*
ObjectivesIn this chapter, you will learn:About database
transactions and their propertiesWhat concurrency control is
and what role it plays in maintaining the database’s
integrityWhat locking methods are and how they workHow
stamping methods are used for concurrency controlHow
optimistic methods are used for concurrency controlHow
database recovery management is used to maintain database
integrity
*
What is a Transaction?A transaction is a logical unit of work
that must be either entirely completed or abortedSuccessful
transaction changes database from one consistent state to
anotherOne in which all data integrity constraints are
satisfiedMost real-world database transactions are formed by
two or more database requestsEquivalent of a single SQL
2. statement in an application program or transaction
Same as Fig. 12.1 in your book
*
Same as Fig. 12.1 in your book
*
Evaluating Transaction Results Not all transactions update the
databaseSQL code represents a transaction because database
was accessedImproper or incomplete transactions can have
devastating effect on database integritySome DBMSs provide
means by which user can define enforceable constraintsOther
integrity rules are enforced automatically by the DBMS
Same as Fig. 12.2 in your book
*
Figure 9.2
Same as Fig. 12.2 in your book
*
Transaction Properties
All transactions must display atomicity, consistency, durability
and serializability (ACIDS).AtomicityAll operations of a
transaction must be completedConsistency Permanence of
database’s consistent stateIsolation Data used during transaction
cannot be used by second transaction until the first is completed
3. *
Transaction Properties (cont..)Durability Once transactions are
committed, they cannot be undoneSerializabilityConcurrent
execution of several transactions yields consistent
resultsMultiuser databases are subject to multiple concurrent
transactions
*
Transaction Management with SQLANSI (American National
Standard Institute) has defined standards that govern SQL
database transactionsTransaction support is provided by two
SQL statements: COMMIT and ROLLBACKTransaction
sequence must continue until:COMMIT statement is
reachedROLLBACK statement is reachedEnd of program is
reachedProgram is abnormally terminated
*
The Transaction LogA DBMS uses a Transaction log to store:A
record for the beginning of transactionFor each transaction
component: Type of operation being performed (update, delete,
insert)Names of objects affected by transaction“Before” and
“after” values for updated fieldsPointers to previous and next
transaction log entries for the same transactionEnding
(COMMIT) of the transaction
Table 12.1 in your book
*
The Transaction Log
Table 12.1 in your book
4. *
Concurrency ControlIs the coordination of simultaneous
transaction execution in a multiprocessing databaseObjective is
to ensure serializability of transactions in a multiuser
environmentSimultaneous execution of transactions over a
shared database can create several data integrity and
consistency problemsLost updatesUncommitted dataInconsistent
retrievals
*
Lost UpdatesLost update problem:Two concurrent transactions
update same data elementOne of the updates is lostOverwritten
by the other transaction
Lost Updates
*
Lost Updates (cont..)
*
5. *
Uncommitted Data Uncommitted data phenomenon:Two
transactions executed concurrentlyFirst transaction rolled back
after second already accessed uncommitted data
Uncommitted Data
*
Uncommitted Data (cont..)
*
*
Inconsistent RetrievalsInconsistent retrievals:First transaction
accesses dataSecond transaction alters the dataFirst transaction
accesses the data againTransaction might read some data before
they are changed and other data after changedYields
inconsistent results
*
6. *
*
The SchedulerSpecial DBMS program Purpose is to establish
order of operations within which concurrent transactions are
executedInterleaves execution of database operations:Ensures
serializabilityEnsures isolationSerializable scheduleInterleaved
execution of transactions yields same results as serial execution
The Scheduler (cont..) Bases its actions on concurrency control
algorithmsEnsures computer’s central processing unit (CPU) is
used efficientlyFacilitates data isolation to ensure that two
transactions do not update same data element at same time
*
*
Database Recovery Management
Database recoveryRestores database from given state, usually
inconsistent, to previously consistent stateBased on atomic
transaction propertyAll portions of transaction treated as single
logical unit of workAll operations applied and completed to
produce consistent database
If transaction operation cannot be completed, transaction must
be aborted, and any changes to database must be rolled back
(undone)
7. Transaction RecoveryMakes use of deferred-write and write-
through techniquesDeferred write Transaction operations do not
immediately update physical databaseOnly transaction log is
updatedDatabase is physically updated only after transaction
reaches its commit point using transaction log information
*
*
Transaction Recovery (cont..)Write-through techniqueDatabase
is immediately updated by transaction operations during
transaction’s execution, even before transaction reaches its
commit pointRecovery processIdentify last checkpointIf
transaction was committed before checkpointDo nothingIf
transaction committed after last checkpointDBMS redoes the
transaction using “after” valuesIf transaction had ROLLBACK
or was left activeDo nothing because no updates were made
Transaction Recovery (cont..)
*
*
8. SummaryTransaction: sequence of database operations that
access databaseLogical unit of workNo portion of transaction
can exist by itselfFive main properties: atomicity, consistency,
isolation, durability, and serializabilityCOMMIT saves changes
to diskROLLBACK restores previous database stateSQL
transactions are formed by several SQL statements or database
requests
*
Summary (cont..) Transaction log keeps track of all transactions
that modify databaseConcurrency control coordinates
simultaneous execution of transactionsScheduler establishes
order in which concurrent transaction operations are
executedLock guarantees unique access to a data item by
transactionTwo types of locks: binary locks and
shared/exclusive locks
*
Summary (cont..) Serializability of schedules is guaranteed
through the use of two-phase lockingDeadlock: when two or
more transactions wait indefinitely for each other to release
lockThree deadlock control techniques: prevention, detection,
and avoidanceTime stamping methods assign unique time stamp
to each transaction Schedules execution of conflicting
transactions in time stamp order
*
Summary (cont..) Optimistic methods assume the majority of
database transactions do not conflictTransactions are executed
concurrently, using private copies of the dataDatabase recovery
9. restores database from given state to previous consistent state
CHAPTER 12: Transaction Management and Concurrency
Control
ADDITIONAL SLIDES pages 635 to 644 in your
Book..
*
*
Two-Phase Locking to Ensure Serializability (cont..)Governed
by the following rules:Two transactions cannot have conflicting
locksNo unlock operation can precede a lock operation in the
same transactionNo data are affected until all locks are
obtained—that is, until transaction is in its locked point
*
Concurrency Control
with Locking MethodsLock Guarantees exclusive use of a data
item to a current transactionRequired to prevent another
transaction from reading inconsistent dataLock
managerResponsible for assigning and policing the locks used
10. by transactions
*
Lock GranularityIndicates level of lock useLocking can take
place at following levels: DatabaseTablePageRowField
(attribute)
*
Lock Granularity (cont..) Database-level lockEntire database is
lockedTable-level lockEntire table is lockedPage-level
lockEntire diskpage is locked Row-level lock Allows concurrent
transactions to access different rows of same tableEven if rows
are located on same page Field-level lock Allows concurrent
transactions to access same row as long as they Require the use
of different fields (attributes) within the row
Fig 12.3 in your book
*
Fig 12.3 in your book
Fig 12.4 in your book
*
Fig 12.4 in your book
Fig. 12.5 in your book
*
11. Lock Granularity (cont..)
Fig. 12.5 in your book
Fig. 12.6 in your book
*
Lock Granularity (cont..)
Fig. 12.6 in your book
*
Lock TypesBinary lockTwo states: locked (1) or unlocked
(0)Exclusive lock Access is specifically reserved for transaction
that locked objectMust be used when potential for conflict
existsShared lock Concurrent transactions are granted read
access on basis of a common lock
Table 12.10 in your book
*
Table 12.10 in your book
*
Two-Phase Locking to Ensure SerializabilityDefines how
transactions acquire and relinquish locksGuarantees
serializability, but does not prevent deadlocks Growing
phaseTransaction acquires all required locks without unlocking
any dataShrinking phaseTransaction releases all locks and
cannot obtain any new lock
12. Deadlocks (cont..)
*
*
DeadlocksCondition that occurs when two transactions wait for
each other to unlock dataPossible only if one of the transactions
wants to obtain an exclusive lock on a data itemNo deadlock
condition can exist among shared locks
*
Table 12.11 in your book
Deadlocks (cont..)
*
Deadlocks (cont..)Three techniques to control
deadlock:Prevention Detection Avoidance Choice of deadlock
control method depends on database environmentLow
probability of deadlock, detection recommendedHigh
probability, prevention recommended
*
Concurrency Control
13. with Time Stamping Methods Assigns global unique time stamp
to each transactionProduces explicit order in which transactions
are submitted to DBMSUniqueness Ensures that no equal time
stamp values can existMonotonicityEnsures that time stamp
values always increase
*
Wait/Die and Wound/Wait SchemesWait/die Older transaction
waits and younger is rolled back and rescheduledWound/wait
Older transaction rolls back younger transaction and
reschedules it
Wait/Die and Wound/Wait Schemes (cont..)
*
*
Concurrency Control
with Optimistic Methods Optimistic approach Based on
assumption that majority of database operations do not
conflictDoes not require locking or time stamping
techniquesTransaction is executed without restrictions until it is
committedPhases: read, validation, and write
14. MA 106 Final Exam Name________________________
Solve by Factoring.
1) �2 + 4� − 5 = 0
2) (� − 2) (� + 5) = 8
Solve.
3) A batter hits a baseball in the air. The height h (in feet) of
the baseball after t seconds is
given by the equation ℎ = −16�2 + 64� + 3 = 0. When is the
baseball at a height of three feet?
Simplify.
16. MA 106 Final Exam Name________________________
9) (� + 2)2 = 36
10) Solve by completing the square.
7x6x
2
11) Solve by using the quadratic formula.
4-x6x
2
Find all values that make the rational expression undefined. If
17. the rational expression is
defined for all real numbers, so state.
12)
18x9x
64x
2
2
Simplify the expression.
13)
2
32
9x3x
x217x
22. MA 106 Final Exam Name________________________
Simplify the complex fraction.
20)
1
a
7
1
a
7
21) The triangles in the figure are similar. Find the length of
the side marked with an x.
24. 10
8
x
5
4
3
Database Principles: Fundamentals of Design, Implementations
and Management
Lecture7- CHAPTER 8 : Beginning Structured Query Language
Presented by Rabia Cherouk
*
ObjectivesIn this chapter, you will learn:The basic commands
and functions of SQLHow to use SQL for data administration
(to create tables, indexes, and views)How to use SQL for data
manipulation (to add, modify, delete, and retrieve data)How to
use SQL to query a database for useful information
*
25. Introduction to SQLSQL functions fit into two broad
categories:Data definition language (DDL)Create database
objects, such as tables, indexes, and viewsDefine access rights
to those database objectsData manipulation language
(DML)SQL is relatively easy to learnBasic command set has
vocabulary of less than 100 words – Non-procedural
languageAmerican National Standards Institute (ANSI)
prescribes a standard SQLand standards are accepted by ISO
(International Organisation for Standardisation) .Several SQL
dialects exist
Introduction to SQL (cont..)
*
Introduction to SQL (cont..)
*
*
Data Definition CommandsThe database modelIn this chapter, a
simple database with these tables is used to illustrate
commands:CUSTOMERINVOICELINEPRODUCTVENDORFoc
us on PRODUCT and VENDOR tables
26. *
The Database Model
Figure 8.1 in your book
The Database Model (cont..)
*
*
Creating the DatabaseTwo tasks must be completed:
1/ Create database structure
2/ Create tables that will hold end-user dataFirst
task:RDBMS creates physical files that will hold
databaseDiffers substantially from one RDBMS to another
*
The Database SchemaAuthentication Process through which
DBMS verifies that only registered users are able to access
databaseLog on to RDBMS using user ID and password created
by database administratorSchemaIs a group of database
objects—such as tables and indexes— that are related to each
other. Usually a schema belongs to a single user or application.
A single database can hold multiple schemas belonging to
different users or applications.
27. *
Data TypesData type selection is usually dictated by nature of
data and by intended usePay close attention to expected use of
attributes for sorting and data retrieval purposesSupported data
types:Number(L,D), Integer, Smallint, Decimal(L,D)Char(L),
Varchar(L), Varchar2(L)Date, Time, TimestampReal, Double,
FloatInterval day to hourMany other types
Data Types (cont..)
*
*
Creating Table StructuresUse one line per column (attribute)
definitionUse spaces to line up attribute characteristics and
constraintsTable and attribute names are capitalizedNOT NULL
specification UNIQUE specification Primary key attributes
contain both a NOT NULL and a UNIQUE specificationRDBMS
will automatically enforce referential integrity for foreign keys
*
Creating Table Structures (cont..)Command sequence ends with
semicolon
Example:
CREATE TABLE EMP_2
( EMP_NUM CHAR(3) NOT NULL UNIQUE,
EMP_LNAME VARCHAR(15) NOT NULL,
EMP_FNAME VARCHAR(15) NOT NULL,
28. EMP_INITIAL CHAR(1),
EMP_HIRE DATE NOT NULL,
JOB_CODE CHAR(3) NOT NULL,
PRIMARY KEY (EMP_NUM),
FOREIGN KEY (JOB_CODE) REFERENCES JOB);
*
SQL ConstraintsNOT NULL constraint Ensures that column
does not accept nullsUNIQUE constraint Ensures that all values
in column are uniqueDEFAULT constraint Assigns value to
attribute when a new row is added to tableCHECK constraint
Validates data when attribute value is entered
*
SQL IndexesWhen primary key is declared, DBMS
automatically creates unique indexOften need additional
indexesUsing CREATE INDEX command, SQL indexes can be
created on basis of any selected attributeComposite indexIndex
based on two or more attributesOften used to prevent data
duplication
SQL Indexes (cont..)
*
29. Data Manipulation CommandsAdding table rowsSaving table
changesListing table rowsUpdating table rowsRestoring table
contentsDeleting table rowsInserting table rows with a select
subquery
*
*
*
Data Manipulation
CommandsINSERTSELECTCOMMITUPDATEROLLBACK
DELETE
*
Adding Table RowsINSERT Used to enter data into
tableSyntax: INSERT INTO columnname
VALUES (value1, value2, … , valueN);
*
Adding Table Rows (cont..)When entering values, notice
that:Row contents are entered between parenthesesCharacter
and date values are entered between apostrophesNumerical
entries are not enclosed in apostrophesAttribute entries are
separated by commasA value is required for each columnUse
NULL for unknown values
30. *
Saving Table ChangesChanges made to table contents are not
physically saved on disk until:Database is closedProgram is
closedCOMMIT command is usedSyntax:COMMIT
[WORK];Will permanently save any changes made to any table
in the database
*
Listing Table RowsSELECT Used to list contents of
tableSyntax: SELECT columnlistFROM tablename;Columnlist
represents one or more attributes, separated by commasAsterisk
can be used as wildcard character to list all attributes
Listing Table Rows (cont..)
*
*
Updating Table RowsUPDATE Modify data in a tableSyntax:
UPDATE tablename
SET columnname = expression [, columnname = expression]
[WHERE conditionlist];If more than one attribute is to be
updated in row, separate corrections with commas
31. *
Restoring Table ContentsROLLBACKUsed to restore database
to its previous conditionOnly applicable if COMMIT command
has not been used to permanently store changes in
databaseSyntax:ROLLBACK;COMMIT and ROLLBACK only
work with manipulation commands that are used to add, modify,
or delete table rows
*
Deleting Table RowsDELETE Deletes a table rowSyntax:
DELETE FROM tablename
[WHERE conditionlist ];WHERE condition is optionalIf
WHERE condition is not specified, all rows from specified table
will be deleted
*
Inserting Table Rows with a
SELECT SubqueryINSERTInserts multiple rows from another
table (source)Uses SELECT subquerySubquery: query that is
embedded (or nested) inside another querySubquery is executed
firstSyntax:
INSERT INTO tablename SELECT columnlist FROM
tablename;
*
32. SELECT QueriesFine-tune SELECT command by adding
restrictions to search criteria using:Conditional
restrictionsArithmetic operatorsLogical operatorsSpecial
operators
*
Selecting Rows with
Conditional RestrictionsSelect partial table contents by placing
restrictions on rows to be included in outputAdd conditional
restrictions to SELECT statement, using WHERE clauseSyntax:
SELECT columnlist
FROM tablelist
[ WHERE conditionlist ] ;
Selecting Rows with
Conditional Restrictions (continued)
*
Selecting Rows with
Conditional Restrictions (continued)
33. *
*
Selecting Rows with
Conditional Restrictions (cont..)
Selecting Rows with
Conditional Restrictions (continued)
*
Selecting Rows with
Conditional Restrictions (cont..)
*
Selecting Rows with
Conditional Restrictions (continued)
34. *
Selecting Rows with
Conditional Restrictions (continued)
*
Selecting Rows with
Conditional Restrictions (cont..)
*
Selecting Rows with
Conditional Restrictions (continued)
*
35. Selecting Rows with
Conditional Restrictions (continued)
*
*
Arithmetic Operators:
The Rule of PrecedencePerform operations within
parenthesesPerform power operationsPerform multiplications
and divisionsPerform additions and subtractionsTable 8.7 in
your book in T
*
Logical Operators: AND, OR, and NOTSearching data involves
multiple conditionsLogical operators: AND, OR, and NOTCan
be combinedParentheses placed to enforce precedence
orderConditions in parentheses always executed firstBoolean
algebra: mathematical field dedicated to use of logical
operatorsNOT negates result of conditional expression
*
36. Special OperatorsBETWEEN: checks whether attribute value is
within a rangeIS NULL: checks whether attribute value is
nullLIKE: checks whether attribute value matches given string
patternIN: checks whether attribute value matches any value
within a value listEXISTS: checks if subquery returns any rows
*
Advanced Data Definition CommandsAll changes in table
structure are made by using ALTER commandThree
optionsADD adds a columnMODIFY changes column
characteristicsDROP deletes a columnCan also be used to: Add
table constraintsRemove table constraints
*
Changing a Column’s Data TypeALTER can be used to change
data typeSome RDBMSs do not permit changes to data types
unless column is empty
Changing a Column’s Data CharacteristicsUse ALTER to
change data characteristicsChanges in column’s characteristics
permitted if changes do not alter the existing data type
*
Adding a Column
Dropping a ColumnUse ALTER to add columnDo not include
the NOT NULL clause for new columnUse ALTER to drop
columnSome RDBMSs impose restrictions on the deletion of an
attribute
37. *
SummarySQL commands can be divided into two overall
categories: Data definition language commands Data
manipulation language commandsThe ANSI standard data types
are supported by all RDBMS vendors in different waysBasic
data definition commands allow you to create tables, indexes,
and views
*
Summary (cont..)DML commands allow you to add, modify, and
delete rows from tablesThe basic DML commands:SELECT,
INSERT, UPDATE, DELETE, COMMIT, and
ROLLBACKSELECT statement is main data retrieval command
in SQL
*
Summary (cont..)WHERE clause can be used with SELECT,
UPDATE, and DELETE statementsAggregate functionsSpecial
functions that perform arithmetic computations over a set of
rowsORDER BY clauseUsed to sort output of SELECT
statementCan sort by one or more columnsAscending or
descending order
*
Summary (cont..)Join output of multiple tables with SELECT
statementJoin performed every time you specify two or more
tables in FROM clauseIf no join condition specified, DBMX
performs Cartesian productNatural join uses join condition to
match only rows with equal values in specified columnsRight
38. outer join and left outer join select rows with no matching
values in other related table
*
Advanced Data UpdatesUPDATE command updates only data in
existing rowsIf relationship between entries and existing
columns, can assign values to slotsArithmetic operators useful
in data updatesIn Oracle, ROLLBACK command undoes
changes made by last two UPDATE statements
*
Advanced Data Updates
*
Copying Parts of TablesSQL permits copying contents of
selected table columnsData need not be reentered manually into
newly created table(s)First create the table structureNext add
rows to new table using table rows from another table
Copying Parts of Tables (cont..)
*
*
39. Adding Primary and Foreign Key DesignationsWhen table is
copied, integrity rules do not copyPrimary and foreign keys
manually defined on new tableUser ALTER TABLE
commandSyntax:
ALTER TABLE tablename
ADD PRIMARY KEY (fieldname);For foreign key, use
FOREIGN KEY in place of PRIMARY KEY
*
Deleting a Table from the DatabaseDROPDeletes table from
databaseSyntax:
DROP TABLE tablename;Can drop a table only if it is not the
“one” side of any relationshipOtherwise RDBMS generates an
error messageForeign key integrity violation
*
Advanced SELECT QueriesLogical operators work well in the
query environmentSQL provides useful functions
that:CountFind minimum and maximum valuesCalculate
averages, etc.SQL allows user to limit queries to:Entries having
no duplicatesEntries whose duplicates may be grouped
*
Ordering a ListingORDER BY clause useful when listing order
importantSyntax:
SELECT columnlist
FROM tablelist
[WHERE conditionlist]
[ORDER BY columnlist [ASC | DESC]];Ascending order
by default
40. Ordering a Listing
*
Ordering a Listing (cont..)
*
Ordering a Listing (cont..)
*
*
Listing Unique ValuesDISTINCT clause produces list of only
values that are different from one anotherExample:
SELECT DISTINCT V_CODE
FROM PRODUCT;Access places nulls at the top of the
listOracle places it at the bottomPlacement of nulls does not
affect list contents
41. Listing Unique Values
*
*
Aggregate FunctionsCOUNT function tallies number of non-null
values of an attributeTakes one parameter: usually a column
nameMAX and MIN find highest (lowest) value in a
tableCompute MAX value in inner queryCompare to each value
returned by the querySUM computes total sum for any specified
attributeAVG function format similar to MIN and MAX
Aggregate Functions
*
Aggregate Functions (cont..)
Figure 8.21 COUNT function output examples
*
42. Aggregate Functions (cont..)
Figure 8.22 MIN and MAX Output Examples
*
Aggregate Functions (cont..)
Figure 8.23 The total values of all items in the PRODUCT table
*
Aggregate Functions (cont..)
Figure 8.24 AVG Function Output Examples
*
*
Grouping DataFrequency distributions created by GROUP BY
clause within SELECT statementSyntax:
SELECT columnlist
FROM tablelist
[WHERE conditionlist]
[GROUP BY columnlist]
[HAVINGconditionlist]
[ORDER BY columnlist [ASC | DESC] ] ;
43. Grouping Data
Figure 8.25 GROUP BY Clause Output Examples
*
Grouping Data (cont..)
Figure 8.27 An application of the HAVING clause
*
*
Virtual Tables: Creating a ViewView is virtual table based on
SELECT queryCreate view by using CREATE VIEW
commandSpecial characteristics of relational view:Name of
view can be used anywhere a table name is expectedView
dynamically updatedRestricts users to only specified columns
and rowsViews may be used as basis for reports
Virtual Tables: Creating a View (cont..)
Figure 8.28 Creating a virtual table using the CREATE VIEW
command
44. *
*
Joining Database TablesAbility to combine (join) tables on
common attributes is most important distinction between
relational database and other databasesJoin is performed when
data are retrieved from more than one table at a timeEquality
comparison between foreign key and primary key of related
tablesJoin tables by listing tables in FROM clause of SELECT
statementDBMS creates Cartesian product of every table
Joining Database Tables (cont..)
*
Joining Database Tables (cont..)
*
*
Joining Tables with an AliasAlias identifies the source table
from which data are takenAlias can be used to identify source
tableAny legal table name can be used as aliasAdd alias after
45. table name in FROM clauseFROM tablename alias
Joining Database Tables (cont..)
*
*
Recursive Joins - Outer JoinsAlias especially useful when a
table must be joined to itselfRecursive queryUse aliases to
differentiate the table from itselfTwo types of outer joinLeft
outer joinRight outer join
Recursive Joins
*
Recursive Joins (cont..)
*
46. Outer Joins
*
Outer Joins (cont..)
*
Grouping Data (cont..)
Figure 8.26 Incorrect and Correct use of the GROUP BY Clause
*
Lect10-Conceptual, Logical and Physical.ppt
9
*
Database Principles: Fundamentals of Design, Implementations
and Management
Lecture 10 - CHAPTER 11: CONCEPTUAL, LOGICAL AND
PHYSICAL DATABASE DESIGN
47. *
9
*
In this chapter, you will learn:About the three stages of
database design: conceptual, logical and physical.How to design
a conceptual model to represent the business and its key
functional areas.How the conceptual model can be transformed
into a logically equivalent set of relations.How to translate the
logical data model into a set of specific DBMS table
specifications.About different types of file organization.How
indexes can be applied to improve data access and retrieval.How
to estimate data storage requirements.
*
9
*
Database DesignNecessary to focus on the dataMust
concentrate on the data characteristics required to build
database modelAt this point there are two views of data within
system:Business view of data as an information
sourceDesigner’s view of the data structure, its access, and
48. activities required to transform data into information
9
*
Database Design (cont..)
9
*
Database Design (cont..)
To complete the design phase, we must remember
these points:The process of database design is loosely related
to analysis and design of larger system The data component is
only one element of a larger systemSystems analysts or systems
programmers are in charge of designing other system
componentsTheir activities create procedures that will help
transform data within database into useful informationThe
Database Design does not constitute a sequential
processIterative process that provides continuous feedback
designed to trace previous steps
9
*
Database Design (cont..)
9
*
3 Stages of Database Design
49. *
9
*
I. Conceptual Design (CD)In the CD, Data modeling is used to
create an abstract database structure that represents real-world
objects in most realistic way possibleThe CD must embody
clear understanding of business and its functional areasEnsure
that all data needed are in the model, and that all data in the
model are neededRequires four steps:Data analysis and
requirementsEntity relationship modeling and
normalisationData model verificationDistributed database
design
9
*
I. Conceptual Design (cont..)Data Analysis and Requirements
First step is to discover the data element characteristicsObtains
characteristics from different sourcesMust take into account the
business rulesDerived from the description of operations which
is a Document that provides precise, detailed, up-to-date, and
thoroughly reviewed description of activities that define
organization’s operating environment
9
*
50. I. Conceptual Design (cont...)Entity Relationship (ER)
Modeling
and Normalization Designer must communicate and enforce
appropriate standards to be used in documentation of designUse
of diagrams and symbolsDocumentation writing
styleLayoutOther conventions to be followed during
documentation
9
*
I. Conceptual Design (cont..)
*
9
*
I. Conceptual Design (cont..)
Fig 11.2 in your book
9
*
I. Conceptual Design (cont..)
51. 9
*
I. Conceptual Design (cont..)
*
9
*
I. Conceptual Design (cont..)
*
9
*
I. Conceptual Design (cont..)Entity Relationship (ER) Modeling
and
Normalization (cont…)Data dictionary Defines all objects
(entities, attributes, relations, views, and so on) Used in tandem
with the normalization process to help eliminate data anomalies
and redundancy problems
52. 9
*
I. Conceptual Design (cont..)The Data Model Verification The
ER Model must be verified against the proposed system
processes to corroborate (confirm) that the intended processes
can be supported by the database modelA revision of the
original design starts with careful reevaluation of the entities,
followed by the detailed examination of the attributes that
describe these entitiesDefine design’s major components as
modules:A module is an information system component that
handles a specific function
9
*
I. Conceptual Design (cont..)
*
9
*
I. Conceptual Design (cont..)
*
53. 9
*
I. Conceptual Design (cont..)Data Model Verification
(cont..)Verification process starts with:Selecting a central
(most important) entityWhich is defined in terms of its
participation in most of the model’s relationshipsThe next step
is to identify the module or subsystem to which central entity
belongs and to define boundaries and scopeOnce the module is
identified, the central entity is placed within module’s
framework
9
*
I. Conceptual Design (cont..)Distributed Database
DesignPortions of the database may reside in different physical
locationsDesigner must also develop data distribution and
allocation strategies
9
*
II. DBMS Software SelectionThe selection of the software is
critical to an information system’s smooth operationAdvantages
and disadvantages should be carefully studiedSome common
factors that may affect the purchasing decision are:CostDBMS
features and toolsUnderlying model: Hierarchical, network,
relational etc…PortabilityDBMS requirements
54. 9
*
III. Logical DesignUsed to translate the conceptual design into
internal model for selected database management systemLogical
design is software-dependentRequires that all objects in the
model be mapped to specific constructs used by selected
database software
9
*
III. Logical Design (cont..)Used to translate the conceptual
design into internal model for the selected database management
systemLogical design is software-dependentThe logical design
stage consists of the following phases:
Creating the logical data model.
Validating the logical data model using normalization.
Assigning and validating integrity constraints.
Merging logical models constructed for different parts for the
database together.
Reviewing the logical data model with the user.
*
9
*
III. Logical Design (cont..)
55. 9
*
III. Logical Design (cont…)
9
*
Review the complete logical model with the userReviewing the
completed logical model with the users to ensure that all the
data requirements have been modelled Ensure that all the
transactions are supported within the different user views. This
stage is very important as any problems need to be solved
before beginning the physical database design stage.
*
9
*
IV. Physical Database DesignPhysical database design requires
the definition of specific storage or access methods that will be
used by the database. Involves the translation of the logical
model into a set of specific DBMS specifications for storing and
accessing data.The ultimate goal must be to ensure that data
storage is effective to ensure integrity and security and efficient
in terms of query response time.
56. *
9
*
IV. Physical Design (cont..)Is the process of selecting data
storage and data access characteristics of the databaseThe
storage characteristics are a function of device types supported
by the hardware, the type of data access methods supported by
the system, and DBMSParticularly important in older
hierarchical and network modelsBecomes more complex when
data are distributed at different locations
9
*
IV. Physical Database Design (cont..)
The following information needs to have been collected:
A set of normalized relations devised from the ER model and
the normalization process.
An estimate of the volume of data which will be stored in each
database table and the usage statistics.
An estimate of the physical storage requirements for each field
(attribute) within the database.
The physical storage characteristics of the DBMS that are being
used
*
57. 9
*
Stages of Physical Database Design
Analysing data volume and database usage.
Translate each relation identified in the logical data model into
a table.
Determine a suitable file organization.
Define indexes.
Define user views.
Estimate data storage requirements.
Determine database security for users.
Additional slides are after the summary
*
9
*
Analysing Data Volume and Database UsageThe steps required
to carrying out this phase are:
Identifying the most frequent and critical transactions.
Analysis of critical transactions to determine which relations in
the database participate in these transactions.
*
58. 9
*
Analysing Data Volume and Database Usage (cont….)Data
volume and data usage statistics are usually shown on a
simplified version of the ERD. This diagram is known as a
composite usage map or a transaction usage map.
*
9
*
Analysing Data Volume and Database Usage (cont….)
*
9
*
Translate logical relations into tables
Identify the primary and any foreign keys for each table.
59. Identify those attributes which are not allowed to contain NULL
values and those which should be UNIQUE. You can exclude
the primary key attribute(s) here as the PRIMARY KEY
constraint automatically imposes the NOT NULL and UNIQUE
constraints.
*
9
*
Translate logical relations into tablesFor each relation you
should:
Identify each attribute name and its domain from the data
dictionary. Note any attributes which require DEFAULT values
to be inserted into the attribute whenever new rows are inserted
into the database.
Determine any attributes that require a CHECK constraint in
order to validate the value of the attribute.
*
9
*
Translate logical relations into tables (continued)
60. *
9
*
Translate logical relations into tables (cont..)
*
9
*
Determine Suitable File OrganisationSelecting the most suitable
file organization is very important to ensure that the data is
stored efficiently and data can be retrieved as quickly as
possible.To do this the DBMS must know where this record is
stored and how it can identify it. Look at the future growth of
the database and whether the type of file organization provides
some protection against data loss.
*
61. 9
*
Determine Suitable File Organisation (cont..)There are three
categories of file organizations:files which contain randomly
ordered records known as heap filesfiles which are sorted on
one or more fields such as file organizations which are based on
indexesfiles hashed on one or more fields known as hash files.
*
9
*
Determine Suitable File Organisation (cont..)Sequential File
OrganizationsRecords are stored in a sequence based on the
value of one or more fields which is often the primary key. In
order to locate a specific record the whole file must be searched
and every record in the file must be read in turn until the
required record is located.
*
9
62. *
Determine Suitable File Organisation (cont..)Heap File
OrganizationsRecords are unordered and inserted into the file as
they come. Only used when a large quantity of data needs to be
inserted into a table for the first time.
*
9
*
Determine Suitable File Organisation (cont..)
*
9
*
Determine Suitable File Organisation (cont..)Indexed File
OrganizationsRecords can be stored in a sorted or unsorted
sequence and an index is created locate specific records
quickly.
63. *
9
*
Determine Suitable File Organisation (cont..)
*
9
*
Determine Suitable File Organisation (cont..)Types of
IndexesPrimary index —these indexes are placed on unique
fields such as the primary key.Secondary index —these indexes
can be placed on any field in the file that is unordered.Multi-
level index —is used where one index becomes too large and so
is split into a number of separate indexes in order to reduce the
search.
*
9
64. *
Determine Suitable File Organisation (cont..)
*
9
*
Determine Suitable File Organisation (cont..)B-treesBalanced or
B-trees and are used to maintain an ordered set of indexes or
data to allow efficient operations to select, delete and insert
data.A special kind of B-tree is known as the B+-tree where all
keys reside in the leaves. This tree is mostoften used to
represent indexes which act as a ‘road_map’ so that each index
can be quickly located
*
9
*
Determine Suitable File Organisation (cont..)
65. *
9
*
Determine Suitable File Organisation (cont..)
*
9
*
Conceptual Design of the DVD rental store
*
9
*
Determine Suitable File Organisation (cont..)
*
66. 9
*
Determine Suitable File Organisation (cont..)Bitmap
IndexesBitmap indexes are usually applied to attributes which
are sparse in their given domain.A two-dimensional array is
constructed. One column is generated for every row in the table
which we want to index with each column representing a
distinct value within the bitmapped index. The two-dimensional
array represents each value within the index multiplied by the
number of rows in the table.
*
9
*
Determine Suitable File Organisation (cont..)
*
9
*
67. Determine Suitable File Organisation (cont..)
*
9
*
Determine Suitable File Organisation (cont..)Bitmap indexes are
usually used when:A column in the table has low cardinality.
The table is not used often for data manipulation activities and
is large.Specific SQL queries reference a number of low
cardinality values in their where clauses.
*
9
*
Determine Suitable File Organisation (cont..)Join IndexCan be
applied to columns from two or more tables whose values come
from the same domain. It is often referred to as a bitmap join
index and it is a way of saving space by reducing the volume of
data that must be joined. The bitmap join stores the ROWIDS of
corresponding rows in a separate table.
69. value onto a specific record address in the file. Records are
stored in a random order throughout the file. Often referred to
as random or direct files.
*
9
*
Define Indexes (cont..)In SQL, indexes are created using the
CREATE INDEX statement. For example, if we wanted to
create a primary index on the DVD_ID primary key field from
the DVDs table the SQL would be:
CREATE UNIQUE INDEX DVDINDEX ON
DVD(DVD_ID)
*
9
*
Define Indexes (cont..)As a general rule, indexes are likely to
be used:When an indexed column appears by itself in a search
criteria of a WHERE or HAVING clause.When an indexed
column appears by itself in a GROUP BY or ORDER BY
clause.When a MAX or MIN function is applied to an indexed
70. column.When the data sparsity on the indexed column is high.
*
9
*
Guidelines for creating IndexesCreate indexes for each single
attribute used in a WHERE, HAVING, ORDER BY, or GROUP
BY clause.Do not use indexes in small tables or tables with low
sparsity.Declare primary and foreign keys so the query
optimizer within a specific DBMS can use the indexes in join
operations.Declare indexes in join columns other than PK/FK.
*
9
*
Define User ViewsDuring the conceptual design stage the
different user views required for the database are
determined.Using the relations defined in the logical data
model, these views must now be defined. Views are often
defined taking database security into account as they can help to
define the roles of different types of users.
71. *
9
*
Estimate Data Storage Requirements
*
9
*
SecurityData must be protected from access by unauthorized
usersMust provide for following: Physical securityPassword
securityAccess rightsAudit trailsData encryptionDiskless
workstations
9
*
Determine database security for usersDuring physical database
design security requirements must be implementedDatabase
privileges for users will need to be established. For example,
privileges may include selecting rows from specified tables or
views, being able to modify or delete data in specified tables
72. etc.
*
9
*
Determine database security for usersDuring physical database
design security requirements must be implementedDatabase
privileges for users will need to be established. For example,
privileges may include selecting rows from specified tables or
views, being able to modify or delete data in specified tables
etc.
*
9
*
Security in ORACLEThe SQL commands GRANT and REVOKE
are used to authorize or withdraw privileges on specific user
accounts. For example, the following two SQL statements grant
the account with the username ‘Craig’ the ability to select rows
from the DVD table and the ability to create tables.
GRANT SELECT ON DVD TO Craig;
GRANT CREATE TABLE TO Craig;
73. *
9
*
Security in ORACLE (cont..)Removing these privileges can be
done using the following SQL statements:
REVOKE SELECT ON MOVIE FROM Craig;
REVOKE CREATE TABLE FROM Craig;
*
9
*
Security in ORACLE (cont..)A role is simply a collection of
privileges referred to under a single name. The major benefit of
roles is that a DBA can add or revoke privileges from a role at
any time. These changes will then automatically apply to all the
users who have been assigned that role.
*
74. 9
*
Security in ORACLE (cont..)For example, in the DVD rental
store, the sales staff need to perform SELECT and UPDATE
operations on the CUSTOMER table. The SQL command
CREATE ROLE is used to create the role
STAFF_CUSTOMER_ROLE:CREATE ROLE
STAFF_CUSTOMER_ROLE;Once created, privileges can then
be granted on selected database objects to the new role.
*
9
*
Security in ORACLE (cont..)For example:
GRANT SELECT ON CUSTOMERS TO
STAFF_CUSTOMER_ROLE;
GRANT UPDATE ON CUSTOMERS TO
STAFF_CUSTOMER_ROLE;The last stage then involves
granting the role to individual users accounts, e.g. Frank:
GRANT STAFF_CUSTOMER_ROLE TO Frank;
*
75. 9
*
SummaryConceptual database design is where the conceptual
representation of the database is created by producing a data
model which identifies the relevant entities and relationships
within the system.
*
9
*
Summary (cont..)Logical database design is the second stage in
the Database Life Cycle, where relations are designed based on
each entity and its relationships within the conceptual model.
*
9
*
76. Summary (cont..)Physical database design is where the logical
data model is mapped onto the physical database tables to be
implemented in the chosen DBMS. The ultimate goal must be to
ensure that data storage is used effectively, to ensure integrity
and security and to improve efficiency in terms of query
response time.
*
9
*
Summary (cont…)Selecting a suitable file organization is
important for fast data retrieval and efficient use of storage
space.Indexes are crucial in speeding up data access. Indexes
facilitate searching, sorting, and using aggregate functions and
even join operations.
*
Chap 2.pptx
Database Principles: Fundamentals of Design, Implementations
and Management
CHAPTER 2: DATA MODELS
102. designThat some situations require denormalization to generate
information efficiently
*
Database Tables and NormalizationNormalization Process for
evaluating and correcting table structures to minimize data
redundanciesReduces data anomaliesWorks through a series of
stages called normal forms: First normal form (1NF)Second
normal form (2NF)Third normal form (3NF)
*
Database Tables and Normalization (cont..)Normalization
(cont..)2NF is better than 1NF; 3NF is better than 2NFFor most
business database design purposes, 3NF is as high as needed in
normalizationHighest level of normalization is not always most
desirableDenormalization produces a lower normal formPrice
paid for increased performance is greater data redundancy
*
The Need for NormalizationExample: company that manages
building projectsCharges its clients by billing hours spent on
each contractHourly billing rate is dependent on employee’s
positionPeriodically, report is generated that contains
information such as displayed in Table 5.1
The Need for Normalization
*
103. The Need for Normalization
*
*
The Need for Normalization (cont..)Structure of data set in
Figure 7.1 does not handle data very wellTable structure
appears to work; report generated with easeUnfortunately report
may yield different results depending on what data anomaly has
occurredRelational database environment suited to help designer
avoid data integrity problems
*
The Normalization ProcessEach table represents a single
subjectNo data item will be unnecessarily stored in more than
one tableAll attributes in a table are dependent on the primary
keyEach table void of insertion, update, deletion anomalies
Void = depourvu de
*
The Normalization Process (cont..)
*
104. *
The Normalization Process (cont..)Objective of normalization is
to ensure all tables in at least 3NFHigher forms not likely to be
encountered in business environmentNormalization works one
relation at a timeProgressively breaks table into new set of
relations based on identified dependencies
*
Conversion to First Normal FormRepeating groupDerives its
name from the fact that a group of multiple entries of same type
can exist for any single key attribute occurrenceRelational table
must not contain repeating groupsNormalizing table structure
will reduce data redundanciesNormalization is three-step
procedure
*
Conversion to First Normal Form (cont.)Step 1: Eliminate the
Repeating Groups Present data in tabular format, where each
cell has single value and there are no repeating groupsEliminate
nulls: each repeating group attribute contains an appropriate
data value
Step 2: Identify the Primary Key Primary key must uniquely
identify attribute valueNew key must be composed
Conversion to First Normal Form (cont..)
*
105. Conversion to First Normal Form (cont..)
*
Conversion to First Normal Form (cont..)Step 3: Identify All
Dependencies Dependencies can be depicted with help of a
diagramDependency diagram: Depicts all dependencies found
within given table structureHelpful in getting bird’s-eye view of
all relationships among table’s attributesMakes it less likely
that will overlook an important dependency
*
Conversion to First Normal Form (cont..)
*
*
Conversion to First Normal Form (cont.)First normal form
describes tabular format in which:All key attributes are
definedThere are no repeating groups in the tableAll attributes
are dependent on primary keyAll relational tables satisfy 1NF
requirementsSome tables contain partial
106. dependenciesDependencies based on part of the primary
keySometimes used for performance reasons, but should be used
with cautionStill subject to data redundancies
Conversion to Second Normal FormRelational database design
can be improved by converting the database into second normal
form (2NF)Two steps
*
*
Conversion to Second Normal Form (cont..)Step 1: Write Each
Key Component
on a Separate Line Write each key component on separate line,
then write original (composite) key on last lineEach component
will become key in new table
Step 2: Assign Corresponding Dependent Attributes Determine
those attributes that are dependent on other attributesAt this
point, most anomalies have been eliminated
Conversion to Second Normal Form (cont..)
*
107. *
Conversion to Second Normal Form (cont..)Table is in second
normal form (2NF) when:It is in 1NF and It includes no partial
dependencies:No attribute is dependent on only portion of
primary key
*
Conversion to Third Normal FormData anomalies created are
easily eliminated by completing three stepsStep 1: Identify Each
New Determinant For every transitive dependency, write its
determinant as PK for new tableDeterminant: any attribute
whose value determines other values within a row
Conversion to Third Normal Form (cont..)Step 2: Identify the
Dependent Attributes Identify attributes dependent on each
determinant identified in Step 1 and identify dependency
Name table to reflect its contents and function
*
*
Conversion to Third Normal Form (cont.)Step 3: Remove the
Dependent Attributes from Transitive Dependencies Eliminate
all dependent attributes in transitive relationship(s) from each
of the tablesDraw new dependency diagram to show all tables
defined in Steps 1–3Check new tables as well as tables modified
in Step 3 to make sure that:Each table has a determinant and
thatNo table contains inappropriate dependencies
108. Conversion to Third Normal Form (cont..)
*
*
Conversion to Third Normal Form (cont.)A table is in third
normal form (3NF) when both of the following are true:It is in
2NFIt contains no transitive dependencies
*
Improving the DesignTable structures are cleaned up to
eliminate troublesome initial partial and transitive dependencies
Normalization cannot, by itself, be relied on to make good
designs
It is valuable because its use helps eliminate data redundancies
*
Improving the Design (cont..)Issues to address in order to
produce a good normalized set of tables: Evaluate PK
AssignmentsEvaluate Naming ConventionsRefine Attribute
AtomicityIdentify New AttributesIdentify New
RelationshipsRefine Primary Keys as Required for Data
GranularityMaintain Historical AccuracyEvaluate Using
Derived Attributes
109. Improving the Design (cont..)
*
Improving the Design (cont..)
*
Improving the Design (cont..)
*
*
Surrogate Key ConsiderationsWhen primary key is considered
to be unsuitable, designers use surrogate keysData entries in
Table 7.3 are inappropriate because they duplicate existing
recordsYet there has been no violation of either entity integrity
or referential integrity
*
Higher-Level Normal FormsTables in 3NF perform suitably in
business transactional databasesHigher order normal forms
useful on occasionTwo special cases of 3NF:Boyce-Codd
normal form (BCNF)Fourth normal form (4NF)
110. *
The Boyce-Codd Normal Form (BCNF)Every determinant in
table is a candidate keyHas same characteristics as primary key,
but for some reason, not chosen to be primary keyWhen table
contains only one candidate key, the 3NF and the BCNF are
equivalentBCNF can be violated only when table contains more
than one candidate key
*
The Boyce-Codd Normal Form (BCNF) (cont..)Most designers
consider the BCNF as special case of 3NFTable is in 3NF when
it is in 2NF and there are no transitive dependenciesTable can
be in 3NF and fails to meet BCNFNo partial dependencies, nor
does it contain transitive dependenciesA nonkey attribute is the
determinant of a key attribute
The Boyce-Codd Normal Form (BCNF) (cont...)
*
The Boyce-Codd Normal Form (BCNF) (cont..)
*
111. The Boyce-Codd Normal Form (BCNF) (cont..)
*
*
SummaryNormalization is used to minimize data
redundanciesFirst three normal forms (1NF, 2NF, and 3NF) are
most commonly encounteredTable is in 1NF when:All key
attributes are definedAll remaining attributes are dependent on
primary key
*
Summary (continued)Table is in 2NF when it is in 1NF and
contains no partial dependenciesTable is in 3NF when it is in
2NF and contains no transitive dependenciesTable that is not in
3NF may be split into new tables until all of the tables meet
3NF requirementsNormalization is important part—but only
part—of the design process
*
Summary (continued)Table in 3NF may contain multivalued
dependencies Numerous null values or redundant dataConvert
3NF table to 4NF by:Splitting table to remove multivalued
dependenciesTables are sometimes denormalized to yield less
I/O, which increases processing speed
Additional SlidesPlease have a look a the following slides
112. *
*
Fourth Normal Form (4NF)Table is in fourth normal form (4NF)
when both of the following are true:It is in 3NF No multiple
sets of multivalued dependencies4NF is largely academic if
tables conform to following two rules:All attributes dependent
on primary key, independent of each otherNo row contains two
or more multivalued facts about an entity
Fourth Normal Form (4NF) (continued)
*
*
Fourth Normal Form (4NF)
Fourth Normal Form (4NF)
*
*
Normalization and Database DesignNormalization should be
part of the design processMake sure that proposed entities meet
113. required normal form before table structures are createdMany
real-world databases have been improperly designed or
burdened with anomaliesYou may be asked to redesign and
modify existing databases
*
Normalization and Database Design (cont.)ER diagram Identify
relevant entities, their attributes, and their relationshipsIdentify
additional entities and attributesNormalization procedures
Focus on characteristics of specific entitiesMicro view of
entities within ER diagramDifficult to separate normalization
process from ER modeling processTwo techniques should be
used concurrently
Figure 7.13 in your book
*
Normalization and Database Design (cont.)
Figure 7.13 in your book
*
Normalization and Database Design (cont.)
Figure 7.14 in your book
Figure 7.14 in your book
*
Figure 7.15 in your book
Normalization and Database Design (cont.)
Figure 7.15 in your book
114. Normalization and Database Design (continued)
*
Normalization and Database Design (continued)
*
Normalization and Database Design (continued)
*
*
*
Void = depourvu de
*
*
*
*
*
116. Database Principles: Fundamentals of Design, Implementations
and Management
Lecture9-CHAPTER 10 : Database Development Process
In this chapter, you will learn:
That successful database design must reflect the information
system of which the database is a part
That successful information systems are developed within a
framework known as the Systems Development Life Cycle
(SDLC)
That within the information system, the most successful
databases are subject to frequent evaluation and revision within
a framework known as the Database Life Cycle (DBLC)
How to conduct evaluation and revision within the SDLC and
DBLC frameworks
2
In this chapter, you will learn (cont..):
About database design strategies: top-down vs. bottom-up
design and centralized vs. decentralized design
Common threats to the security of the data and what security
measures could be put in place
The importance of the database administration in an
organization
The technical and managerial roles of the database
administrator (DBA)
117. 3
The Information System
Provides for data collection, storage, and retrieval
Composed of people, hardware, software, database(s),
application programs, and procedures
Systems analysis
Is the process that establishes the need for and extent of an
information system
Systems development
Is the process of creating information system
4
The Information System (cont..)
Applications
Transform data into information that forms the basis for
decision making
Usually produce the following:
Formal report
Tabulations
Graphic displays
Composed of following two parts:
Data
Code by which data are transformed into information
5
118. The Information System (cont..)
6
The Information System (cont..)
Information system performance depends on triad of factors:
Database design and implementation
Application design and implementation
Administrative procedures
Database development
Is the process of database design and implementation
The primary objective is to create complete, normalized, non-
redundant (to the extent possible), and fully integrated
conceptual, logical, and physical database models
7
The Systems Development Life Cycle (SDLC)
Traces history (life cycle) of information system
Provides “big picture” within which database design and
application development can be mapped out and evaluated
Divided into following five phases:
Planning
Analysis
Detailed systems design
Implementation
Maintenance
Iterative rather than sequential process
119. 8
The Systems Development Life Cycle (SDLC) (cont..)
9
Planning
Yields a general overview of the company and its objectives
Is an initial assessment made of information-flow-and-extent
requirements
Must begin to study and evaluate alternate solutions
Technical aspects of hardware and software requirements
System cost
10
Analysis
The problems defined during planning phase are examined in
greater detail during analysis
Thorough audit of user requirements
The existing hardware and software systems are studied
Goal is a better understanding of :
system’s functional areas,
The actual and potential problems,
and opportunities
120. 11
Analysis (cont..)
Includes the creation of logical system design
Must specify appropriate conceptual data model, inputs,
processes, and expected output requirements
Might use tools such as data flow diagrams (DFDs), hierarchical
input process output (HIPO) diagrams, and entity relationship
(ER) diagrams
Yields functional descriptions of system’s components
(modules) for each process within database environment
12
Detailed Systems Design
The designer completes the design of the system’s processes
Includes all necessary technical specifications
The steps are laid out for conversion from old to new system
The training principles and methodologies are also planned
Submitted for management approval
13
Implementation
Hardware, DBMS software, and application programs are
121. installed,
and the database design is implemented
The system enters into:
A cycle of coding,
Testing, and debugging continues until it is ready to be
delivered
The actual database is created and the system is customized by
creation of tables and views,
and user authorizations
14
Maintenance
Maintenance activities can be grouped into three types:
Corrective maintenance in response to systems errors
Adaptive maintenance due to changes in business environment
Perfective maintenance to enhance system
Computer-assisted systems engineering (CASE)
Make it possible to produce better systems within reasonable
amount of time and at reasonable cost
CASE-produced applications are structured, documented,
standardized
15
16
The Database Life Cycle (DBLC)
Six phases:
Database initial study
122. Database design
Implementation and loading
Testing and evaluation
Operation
Maintenance and evolution
The Database Life Cycle (DBLC)
17
The Database Initial Study
Overall purpose:
Analyze company situation
Define problems and constraints
Define objectives
Define scope and boundaries
Fig 10.4 in the next slide depicts the interactive and iterative
processes required to complete first phase of DBLC successfully
18
The Database Initial Study (cont..)
Fig 10.4 in your book
19
123. Analyze the Company Situation
Analysis–To break up any whole into its parts so as to find out
their nature, function, and so on
Company situation
General conditions in which company operates, its
organizational structure, and its mission
Analyze company situation
Discover what company’s operational components are, how they
function, and how they interact
20
Define Problems and Constraints
Managerial view of company’s operation is often different from
that of end users
The Database Designer must continue to carefully probe to
generate additional information that will help define problems
within larger framework of company operations
Finding precise answers is important
Defining problems does not always lead to perfect solution
21
Define Objectives
Designer must ensure that database system objectives
correspond to those envisioned by end user(s)
Designer must begin to address following questions:
124. What is proposed system’s initial objective?
Will system interface with other existing or future systems in
the company?
Will system share data with other systems or users?
22
Define Scope and Boundaries
Scope
Defines extent of design according to operational requirements
Helps define required data structures, type and number of
entities, and physical size of database
Boundaries
Limits external to system
Often imposed by existing hardware and software
23
Database Design
Necessary to concentrate on data
Characteristics required to build database model
Two views of data within system:
Business view of
data as information source
Designer’s view of
data structure, its access, and activities required to transform
data into information
24
125. Database Design (cont..)
Fig 10.5 in your book
25
Database Design (cont..)
Loosely related to analysis and design of larger system
The Systems analysts or systems programmers are in charge of
designing other system components
Their activities create procedures that will help transform data
within database into useful information
Does not constitute sequential process
Iterative process that provides continuous feedback designed to
trace previous steps
26
Database Design (cont..)
27
I. Conceptual Design Overview
126. Data modeling used to create an abstract database structure
that represents real-world objects in most realistic way possible
Must embody clear understanding of business and its functional
areas
Ensure that all data needed are in model, and that all data in the
model are needed
28
I. Conceptual Design Overview (cont..)
Requires four steps
Data analysis and requirements
Discover data element characteristics
Obtains characteristics from different sources
Take into account business rules
Derived from description of operations
Entity relationship modeling and normalization
Designer enforces standards in design documentation
Use of diagrams and symbols, documentation writing style,
layout, other conventions
29
30
I. Conceptual Design Overview (cont..)
3. Data model verification
Verified against proposed system processes
Revision of original design
Careful reevaluation of entities
127. Detailed examination of attributes describing entities
Define design’s major components as modules:
Module: information system component that handles specific
function
31
I. Conceptual Design Overview (cont..)
Data model verification (cont…)
Verification process
Select central (most important) entity
Defined in terms of its participation in most of model’s
relationships
Identify module or subsystem to which central entity belongs
and define boundaries and scope
Place central entity within module’s framework
32
I. Conceptual Design Overview(cont..)
Distributed database design
Portions of the database may reside in different physical
locations
Processes accessing the database vary from one location to
another
The Designer must also develop data distribution and allocation
strategies
II. DBMS Software Selection
Critical to information system’s smooth operation
Common factors affecting purchasing decisions:
Cost
DBMS features and tools
Underlying model
128. Portability
DBMS hardware requirements
Advantages and disadvantages should be carefully studied
33
III. Logical Design Overview
Used to translate conceptual design into internal model for
selected database management system
Logical design is software-dependent
Requires that all objects in model be mapped to specific
constructs used by selected database software
Definition of attribute domains, design of required tables,
access restriction formats
Tables must correspond to entities in conceptual design
Translates software-independent conceptual model into
software-dependent logical model
34
III. Logical Design Overview (cont..)
The logical design stage consists of the following phases:
Creating the logical data model.
Validating the logical data model using normalization.
Assigning and validating integrity constraints.
Merging logical models constructed for different parts for the
129. database together.
Reviewing the logical data model with the use
35
IV. Physical Design Overview
Is the Process of selecting data storage and data access
characteristics of database
Storage characteristics are function of device types supported
by hardware, type of data access methods supported by system,
and DBMS
Particularly important in older hierarchical and network models
Becomes more complex when data are distributed at different
locations
36
IV. Physical Design Overview (cont..)
Physical database design can be broken down into a number of
stages:
Analyze data volume and database usage.
Translate each relation identified in the logical data model into
tables.
Determine a suitable file organization.
Define indexes.
Define user views.
Estimate data storage requirements.
Determine database security for users.
130. 37
Implementation and Loading
New database implementation requires creation of special
storage-related constructs to house end-user tables
38
Performance
Is one of the most important factors in certain database
implementations
Not all DBMSs have performance-monitoring and fine-tuning
tools embedded in their software
Performance evaluation is rendered more difficult as there is no
standard measurement for database performance
39
Backup and Recovery
Database can be subject to data loss through unintended data
deletion and power outages
Data backup and recovery procedures
Create safety valve
Allow database administrator to ensure availability of consistent
131. data
Integrity
Enforced through proper use of primary and foreign key rules
40
Company Standards
May partially define database standards
Database administrator must implement and enforce such
standards
Database Security
Data must be protected from access by unauthorized users
Establish security goals
- What are we trying to protect the database from?
- What security related problems are we trying to prevent?
The most common security goals relate to the integrity,
confidentiality and the availability of data.
41
Data Security Measures
Physical security allows only authorized personnel physical
access to specific areas.
User authentication is a way of identifying the user and
verifying that the user is allowed to access some restricted data
or application.
achieved through the use of passwords and access rights.
Audit trails are usually provided by the DBMS to check for
access violations.
132. 42
Data Security Measures (cont..)
Data encryption
Can be used to render data useless to unauthorised users.
ORACLE DBMS has a Transparent Data Encryption
User-defined policies and procedures
Backup and recovery strategies should be in place in the event
of a disaster occurring
Antivirus software
Firewalls are systems comprising of hardware devices or
software applications which act as gatekeepers to an
organisation’s network.
For more details on security measures read the slides after the
chapter summary
43
Testing and Evaluation
This phase occurs in parallel with applications programming
Programmers use database tools to prototype applications
during coding of the programs
If the DB implementation fails to meet some of system’s
evaluation criteria, several options may be considered to
enhance the system:
Fine-tune specific system and DBMS configuration parameters
Modify physical design
133. Modify logical design
Upgrade or change DBMS software and/or hardware platform
44
Operation
Once the database has passed the evaluation stage, it is
considered operational
The beginning of the operational phase starts the process of
system maintenance and evolution
45
Maintenance and Evolution
Required periodic maintenance:
Preventive maintenance (backup)
Corrective maintenance (recovery)
Adaptive maintenance
Assignment of access permissions and their maintenance for
new and old users
Generation of database access statistics
Periodic security audits
Periodic system-usage summaries
46
Parallel Activities in the DBLC and the SDLC
134. 47
Summary
Information system is designed to facilitate transformation of
data into information and to manage both data and information
SDLC traces history (life cycle) of an application within the
information system
DBLC describes history of database within the information
system
Database design and implementation process moves through
series of well-defined stages
Conceptual portion of design may be subject to several
variations, based on two design philosophies
48
Summary (cont..)
Threats to database security include the loss of integrity,
confidentiality and availability of data.
The database administrator (DBA) is responsible for managing
the corporate database.
The development of the data administration strategy is closely
related to the company’s mission and objectives.
49
135. Threats to Security
Threats are any set of circumstances that have the potential to
cause loss, misuse or harm to the system and/or its data.
Threats can cause:
The loss of the integrity of data through unauthorized
modification.
For example a person gaining unauthorized access to a bank
account and removing some money from the account.
50
Threats to Security
The loss of availability of the data.
For example some adversary causes the database system from
being operational which stops authorized users of the data from
accessing it.
The loss of confidentiality of the data (also referred to as the
privacy of data).
This could be caused by a person gaining access to private
information such as a password or a bank account balance.
51
Examples of Threats
Theft and fraud of data.
Human error which causes accidental loss of data.
136. Electronic infections
Viruses
Email Viruses
Worms
Trojan Horses
52
Examples of Threats (cont..)
The occurrence of natural disasters such as hurricanes, fires or
floods.
Unauthorized access and modification of data.
Employee sabotage is concerned with the deliberate acts of
malice against the organization.
Poor database administration.
53
Examples of Threats (cont..)
54
Database Design Strategies
Two classical approaches to database design:
Top-down design
137. Identifies data sets
Defines data elements for each of those sets
Bottom-up design
Identifies data elements (items)
Groups them together in data sets
55
Database Design Strategies Top-down vs. bottom-up design
sequencing
56
Centralized vs. Decentralized Design
Database design may be based on two very different design
philosophies:
Centralized design
Productive when data component is composed of relatively
small number of objects and procedures
Decentralized design
Used when data component of system has considerable number
of entities and complex relations on which very complex
operations are performed
57
138. Centralized vs. Decentralized Design Centralized Design
58
Decentralized Design
59
Centralized vs. Decentralized Design (cont..)
Aggregation process
Requires designer to create single model in which various
aggregation problems must be addressed:
Synonyms and homonyms
Entity and entity subtypes
Conflicting object definitions
60
Centralized vs. Decentralized Design Summary of aggregation
problems
61
139. Database Administration
Data management is a complex job
Led to the development of the database administration function.
The person responsible for the control of the centralized and
shared database is the database administrator (DBA).
62
DBA Activities
Database planning, including the definition of standards,
procedures and enforcement.
Database requirements gathering and conceptual design.
Database logical design and transaction design.
63
DBA Activities (cont..)
Database physical design and implementation.
Database testing and debugging.
Database operations and maintenance, including installation,
conversion and migration.
Database training and support.
64
140. The DBA in the Organisation
65
DBA Skills
66
The Managerial Role of the DBA
67
The Managerial Role of the DBA (cont..)
End-User Support
Gathering user requirements
Building end-user confidence.
Resolving conflicts and problems.
Finding solutions to information needs.
Ensuring quality and integrity of applications and data.
Managing the training and support of DBMS users.
68
141. The Managerial Role of the DBA (cont..)
Policies, Procedures and Standards
Policies are general statements of direction or action that
communicate and support DBA goals.
Standards are more detailed and specific than policies and
describe the minimum requirements of a given DBA activity.
Procedures are written instructions that describe a series of
steps to be followed during the performance of a given activity.
69
The Managerial Role of the DBA (cont..)
Data Security, Privacy and Integrity
Protecting the security and privacy of the data in the database is
a function of authorization management.
Authorization management defines procedures to protect and
guarantee database security and integrity.
Includes: user access management, view definition, DBMS
access control and DBMS usage monitoring.
70
The Managerial Role of the DBA (cont..)
Data Backup and Recovery
Many DBA departments have created a position staffed by the
database security officer (DSO).
142. The DSO’s activities are often classified as disaster
management.
Disaster management includes all of the DBA activities
designed to secure data availability following a physical
disaster or a database integrity failure.
Disaster management includes all planning, organizing and
testing of database contingency plans and recovery procedures.
71
The Managerial Role of the DBA (cont..)
Data Distribution and Use
The DBA is responsible for ensuring that the data are
distributed to the right people, at the right time and in the right
format.
72
The Technical Role of the DBA
Evaluating, selecting and installing the DBMS and related
utilities.
Designing and implementing databases and applications.
Testing and evaluating databases and applications.
Operating the DBMS, utilities and applications.
Training and supporting users.
Maintaining the DBMS, utilities and applications.
143. 73
Evaluating, Selecting and Installing the DBMS and Utilities
(DBA)
Covers the selection of the database management system, utility
software and supporting hardware for use in the organization.
Must be based primarily on the organization’s needs
The DBA would be wise to develop a checklist of desired
DBMS features.
74
Designing and Implementing Databases and Applications (DBA)
Covers data modelling and design services to the end-user
community
Determine and enforce standards and procedures to be used.
DBA then provides the necessary assistance and support during
the design of the database at the conceptual, logical and
physical levels
75
Testing and Evaluating Databases and Applications (DBA)
The DBA must also provide testing and evaluation services for
all of the database and end-user applications.
Those services are the logical extension of the design,
development and implementation services.