The document describes the network database model and CODASYL DBTG model. Some key points:
- The network model uses a many-to-many relationship with owner and member records linked together.
- The DBTG model simplified this to one-to-one and one-to-many relationships. It uses segments, sets, and links to represent records, relationships, and connections between records.
- The DBTG model provides commands to retrieve, update, insert, and delete records as well as connect and disconnect them from sets. Programs access the database using templates, pointers, and status flags stored in a work area.
The document discusses database management systems and their advantages over traditional file systems. It covers key concepts such as:
1) Databases organize data into tables with rows and columns to allow for easier querying and manipulation of data compared to file systems which store data in unstructured files.
2) Database management systems employ concepts like normalization, transactions, concurrency and security to maintain data integrity and consistency when multiple users are accessing the data simultaneously.
3) The logical design of a database is represented by its schema, while a database instance refers to the current state of the data stored in the database tables at a given time.
The document discusses data modeling, which involves creating a conceptual model of the data required for an information system. There are three types of data models - conceptual, logical, and physical. A conceptual data model describes what the system contains, a logical model describes how the system will be implemented regardless of the database, and a physical model describes the implementation using a specific database. Common elements of a data model include entities, attributes, and relationships. Data modeling is used to standardize and communicate an organization's data requirements and establish business rules.
This document defines database and DBMS, describes their advantages over file-based systems like data independence and integrity. It explains database system components and architecture including physical and logical data models. Key aspects covered are data definition language to create schemas, data manipulation language to query data, and transaction management to handle concurrent access and recovery. It also provides a brief history of database systems and discusses database users and the critical role of database administrators.
Dbms classification according to data modelsABDUL KHALIQ
CLASSIFICATION ACCORDING TO DATA MODELS
Hierarchal Model
In a hierarchical data model, data are organized into a tree-like structure.
Network Model
based on an enlargement of the concept of hierarchical data bases.
Relational Model
Data are stored in tables
Object Oriented model
Object oriented data base systems are the most recent development in data base technology.
Introduction
Definations
Advantages and Disadvantages
PowerPoint Presentation
PowerPoint Presentation for free
The document provides an overview of databases and database design. It defines what a database is, what databases do, and the components of database systems and applications. It discusses the database design process, including identifying fields, tables, keys, and relationships between tables. The document also covers database modeling techniques, normalization to eliminate redundant or inefficient data storage, and functional dependencies as constraints on attribute values.
The document discusses the relational database model. It was introduced in 1970 and became popular due to its simplicity and mathematical foundation. The model represents data as relations (tables) with rows (tuples) and columns (attributes). Keys such as primary keys and foreign keys help define relationships between tables and enforce integrity constraints. The relational model provides a standardized way of structuring data through its use of relations, attributes, tuples and keys.
The document discusses database management systems and their advantages over traditional file systems. It covers key concepts such as:
1) Databases organize data into tables with rows and columns to allow for easier querying and manipulation of data compared to file systems which store data in unstructured files.
2) Database management systems employ concepts like normalization, transactions, concurrency and security to maintain data integrity and consistency when multiple users are accessing the data simultaneously.
3) The logical design of a database is represented by its schema, while a database instance refers to the current state of the data stored in the database tables at a given time.
The document discusses data modeling, which involves creating a conceptual model of the data required for an information system. There are three types of data models - conceptual, logical, and physical. A conceptual data model describes what the system contains, a logical model describes how the system will be implemented regardless of the database, and a physical model describes the implementation using a specific database. Common elements of a data model include entities, attributes, and relationships. Data modeling is used to standardize and communicate an organization's data requirements and establish business rules.
This document defines database and DBMS, describes their advantages over file-based systems like data independence and integrity. It explains database system components and architecture including physical and logical data models. Key aspects covered are data definition language to create schemas, data manipulation language to query data, and transaction management to handle concurrent access and recovery. It also provides a brief history of database systems and discusses database users and the critical role of database administrators.
Dbms classification according to data modelsABDUL KHALIQ
CLASSIFICATION ACCORDING TO DATA MODELS
Hierarchal Model
In a hierarchical data model, data are organized into a tree-like structure.
Network Model
based on an enlargement of the concept of hierarchical data bases.
Relational Model
Data are stored in tables
Object Oriented model
Object oriented data base systems are the most recent development in data base technology.
Introduction
Definations
Advantages and Disadvantages
PowerPoint Presentation
PowerPoint Presentation for free
The document provides an overview of databases and database design. It defines what a database is, what databases do, and the components of database systems and applications. It discusses the database design process, including identifying fields, tables, keys, and relationships between tables. The document also covers database modeling techniques, normalization to eliminate redundant or inefficient data storage, and functional dependencies as constraints on attribute values.
The document discusses the relational database model. It was introduced in 1970 and became popular due to its simplicity and mathematical foundation. The model represents data as relations (tables) with rows (tuples) and columns (attributes). Keys such as primary keys and foreign keys help define relationships between tables and enforce integrity constraints. The relational model provides a standardized way of structuring data through its use of relations, attributes, tuples and keys.
The document discusses different types of data models and their evolution. It describes hierarchical, network, relational, entity relationship, and object oriented models. Each new model aimed to improve on limitations of previous approaches. The models can be classified at different levels of abstraction, from external views specific to business units to conceptual and internal representations within the database.
This document discusses different data models used in database management systems including record-based, relational, network, hierarchical, and entity-relationship models. It provides details on each model such as how data is organized. A record-based model uses fixed-length records and fields. The relational model organizes data into tables with rows and columns. The network model links entities through multiple paths in a graph structure. The hierarchical model arranges data in a tree structure. Finally, the entity-relationship model views the real world as entities and relationships between entities.
The document provides an introduction to database management systems (DBMS) and database models. It defines key terms like data, database, DBMS, file system vs DBMS. It describes the evolution of DBMS from 1960 onwards and different database models like hierarchical, network and relational models. It also discusses the roles of different people who work with databases like database designers, administrators, application programmers and end users.
The document discusses different database concepts:
1) A database is a collection of organized data that can be easily retrieved, inserted, and deleted. Database management systems (DBMS) like MySQL and Oracle are software used to manage databases.
2) The two main data models are the relational model, which organizes data into tables and relations, and the object-oriented model, which represents data as objects with properties and methods.
3) DBMS provide advantages like data sharing, backup/recovery, security, and independence between data and applications. However, they also have disadvantages such as higher costs and complexity.
This document provides an overview of database management systems and related concepts. It discusses data hierarchy, traditional file processing, the database approach to data management, features and capabilities of database management systems, database schemas, components of database management systems, common data models including hierarchical, network, and relational models, and the process of data normalization.
This document defines SGML and discusses its advantages and disadvantages. SGML stands for Standard Generalized Markup Language, which is a system for organizing and tagging elements of a document. It allows authors to markup documents with structural, presentational, and semantic information. Some advantages of SGML include its flexibility, separation of content from appearance, and support of different media types. However, SGML also has disadvantages such as complex DTDs, linking, and software development.
This document provides an overview of data modeling, including definitions of key concepts like data models and data modeling. It describes the evolution of popular data models from hierarchical to network to relational to entity-relationship to object-oriented models. For each model, it outlines the basic concepts, advantages, and disadvantages. The document emphasizes that newer data models aimed to address shortcomings of previous approaches and capture real-world data and relationships.
A database management system (DBMS) is software that allows for the creation, management, and use of databases. A DBMS provides users and administrators with various tools and applications to store, organize, and access data. It allows for data to be easily retrieved, filtered, sorted, and updated efficiently. Some key components of a DBMS include the database users, the data itself, software and procedures, hardware, and database access languages. DBMSs are widely used in applications such as banking, universities, e-commerce, and more.
This document discusses different types of data models, including hierarchical, network, relational, and object-oriented models. It focuses on explaining the relational model. The relational model organizes data into tables with rows and columns and handles relationships using keys. It allows for simple and symmetric data retrieval and integrity through mechanisms like normalization. The relational model is well-suited for the database assignment scenario because it supports linking data across multiple tables using primary and foreign keys, and provides query capabilities through SQL.
This document discusses object query language (OQL) and the six-layer architecture model for object-oriented databases. It provides an overview of OQL, describing how it is based on SQL but extends it to support object-oriented notions. It also outlines the main components of the six-layer model - the interaction layer, application layer, administrative layer, security layer, virtual layer, and paging layer - and describes their basic responsibilities in managing and securing object-oriented data. Finally, it briefly lists some disadvantages of object-oriented database management systems.
This chapter introduces database systems and their advantages over traditional file systems. It discusses the components of a database system including the database, database management system (DBMS), and their roles in data storage and access. Databases have evolved from file systems to address issues like data redundancy, inconsistency, and dependence on structure and storage characteristics. The chapter outlines different types of databases and the importance of database design. It provides examples of problems in traditional file system data management to illustrate improvements made by modern database systems.
The document discusses the architecture and components of a database management system (DBMS). It describes that a DBMS is divided into modules including a query processor and storage manager. The query processor receives and optimizes SQL queries, while the storage manager is responsible for storing, retrieving, and updating data through components like a buffer manager, file manager, and transaction manager. The document also outlines some common data structures used in a DBMS like data files, data dictionaries, and indices.
Oracle Database is a collection of data treated as a unit. The purpose of a database is to store and retrieve related information. Oracle Database was started in 1977 as Software Development Laboratories by Larry Ellison and others. Over time, Oracle released several major versions that added new functionality, such as Oracle 12c which was designed for cloud computing. A database server is the key to solving problems of information management by allowing storage, retrieval, and manipulation of data.
Relational databases vs Non-relational databasesJames Serra
There is a lot of confusion about the place and purpose of the many recent non-relational database solutions ("NoSQL databases") compared to the relational database solutions that have been around for so many years. In this presentation I will first clarify what exactly these database solutions are, compare them, and discuss the best use cases for each. I'll discuss topics involving OLTP, scaling, data warehousing, polyglot persistence, and the CAP theorem. We will even touch on a new type of database solution called NewSQL. If you are building a new solution it is important to understand all your options so you take the right path to success.
The document discusses various types of physical storage media used in databases, including their characteristics and performance measures. It covers volatile storage like cache and main memory, and non-volatile storage like magnetic disks, flash memory, optical disks, and tape. It describes how magnetic disks work and factors that influence disk performance like seek time, rotational latency, and transfer rate. Optimization techniques for disk block access like file organization and write buffering are also summarized.
This document describes four types of databases: hierarchical, network, relational, and object-oriented. Hierarchical databases organize data in a tree structure with parent-child relationships. Network databases use a many-to-many relationship structure like a graph. Relational databases organize data into tables with rows and columns. Object-oriented databases store reusable software objects that contain data and instructions.
Distributed database management systemsDhani Ahmad
This chapter discusses distributed database management systems (DDBMS). A DDBMS governs storage and processing of logically related data across interconnected computer systems. The chapter covers DDBMS components, levels of data and process distribution, transaction management, and design considerations like data fragmentation, replication, and allocation. Transparency and optimization techniques aim to make the distributed nature transparent to users.
The document discusses deductive databases and how they differ from conventional databases. Deductive databases contain facts and rules that allow implicit facts to be deduced from the stored information. This reduces the amount of storage needed compared to explicitly storing all facts. Deductive databases use logic programming through languages like Datalog to specify rules that define virtual relations. The rules allow new facts to be inferred through an inference engine even if they are not explicitly represented.
The document introduces web services and the .NET framework. It defines a web service as a network-accessible interface that allows applications to communicate over the internet using standard protocols. It describes the key components of a web service including SOAP, WSDL, UDDI, and how they allow services to be described, discovered and accessed over a network in a standardized way. It also provides an overview of the .NET framework and how it supports web services and applications using common languages like C#.
A great power point presentation for DBMS Concepts from start to end and with best examples chapter by chapter. Please go though each chapters sequentially for your knowledge.
A very easy going study material for better understanding and concepts of Database Management System!
This document discusses the conversion of Montgomery County Public Schools' student systems from a legacy IDMS database to an Oracle database. It summarizes the current and planned processes for generating administrative reports, enrollment data for the Department of Reporting and Regulatory Accountability, and data for special education. The administrative reports and enrollment data will initially be generated using a legacy extract uploaded to Oracle tables, before being produced directly from Oracle in the future. Special education data will also transition from the legacy system to Oracle tables and processes.
The document discusses different types of data models and their evolution. It describes hierarchical, network, relational, entity relationship, and object oriented models. Each new model aimed to improve on limitations of previous approaches. The models can be classified at different levels of abstraction, from external views specific to business units to conceptual and internal representations within the database.
This document discusses different data models used in database management systems including record-based, relational, network, hierarchical, and entity-relationship models. It provides details on each model such as how data is organized. A record-based model uses fixed-length records and fields. The relational model organizes data into tables with rows and columns. The network model links entities through multiple paths in a graph structure. The hierarchical model arranges data in a tree structure. Finally, the entity-relationship model views the real world as entities and relationships between entities.
The document provides an introduction to database management systems (DBMS) and database models. It defines key terms like data, database, DBMS, file system vs DBMS. It describes the evolution of DBMS from 1960 onwards and different database models like hierarchical, network and relational models. It also discusses the roles of different people who work with databases like database designers, administrators, application programmers and end users.
The document discusses different database concepts:
1) A database is a collection of organized data that can be easily retrieved, inserted, and deleted. Database management systems (DBMS) like MySQL and Oracle are software used to manage databases.
2) The two main data models are the relational model, which organizes data into tables and relations, and the object-oriented model, which represents data as objects with properties and methods.
3) DBMS provide advantages like data sharing, backup/recovery, security, and independence between data and applications. However, they also have disadvantages such as higher costs and complexity.
This document provides an overview of database management systems and related concepts. It discusses data hierarchy, traditional file processing, the database approach to data management, features and capabilities of database management systems, database schemas, components of database management systems, common data models including hierarchical, network, and relational models, and the process of data normalization.
This document defines SGML and discusses its advantages and disadvantages. SGML stands for Standard Generalized Markup Language, which is a system for organizing and tagging elements of a document. It allows authors to markup documents with structural, presentational, and semantic information. Some advantages of SGML include its flexibility, separation of content from appearance, and support of different media types. However, SGML also has disadvantages such as complex DTDs, linking, and software development.
This document provides an overview of data modeling, including definitions of key concepts like data models and data modeling. It describes the evolution of popular data models from hierarchical to network to relational to entity-relationship to object-oriented models. For each model, it outlines the basic concepts, advantages, and disadvantages. The document emphasizes that newer data models aimed to address shortcomings of previous approaches and capture real-world data and relationships.
A database management system (DBMS) is software that allows for the creation, management, and use of databases. A DBMS provides users and administrators with various tools and applications to store, organize, and access data. It allows for data to be easily retrieved, filtered, sorted, and updated efficiently. Some key components of a DBMS include the database users, the data itself, software and procedures, hardware, and database access languages. DBMSs are widely used in applications such as banking, universities, e-commerce, and more.
This document discusses different types of data models, including hierarchical, network, relational, and object-oriented models. It focuses on explaining the relational model. The relational model organizes data into tables with rows and columns and handles relationships using keys. It allows for simple and symmetric data retrieval and integrity through mechanisms like normalization. The relational model is well-suited for the database assignment scenario because it supports linking data across multiple tables using primary and foreign keys, and provides query capabilities through SQL.
This document discusses object query language (OQL) and the six-layer architecture model for object-oriented databases. It provides an overview of OQL, describing how it is based on SQL but extends it to support object-oriented notions. It also outlines the main components of the six-layer model - the interaction layer, application layer, administrative layer, security layer, virtual layer, and paging layer - and describes their basic responsibilities in managing and securing object-oriented data. Finally, it briefly lists some disadvantages of object-oriented database management systems.
This chapter introduces database systems and their advantages over traditional file systems. It discusses the components of a database system including the database, database management system (DBMS), and their roles in data storage and access. Databases have evolved from file systems to address issues like data redundancy, inconsistency, and dependence on structure and storage characteristics. The chapter outlines different types of databases and the importance of database design. It provides examples of problems in traditional file system data management to illustrate improvements made by modern database systems.
The document discusses the architecture and components of a database management system (DBMS). It describes that a DBMS is divided into modules including a query processor and storage manager. The query processor receives and optimizes SQL queries, while the storage manager is responsible for storing, retrieving, and updating data through components like a buffer manager, file manager, and transaction manager. The document also outlines some common data structures used in a DBMS like data files, data dictionaries, and indices.
Oracle Database is a collection of data treated as a unit. The purpose of a database is to store and retrieve related information. Oracle Database was started in 1977 as Software Development Laboratories by Larry Ellison and others. Over time, Oracle released several major versions that added new functionality, such as Oracle 12c which was designed for cloud computing. A database server is the key to solving problems of information management by allowing storage, retrieval, and manipulation of data.
Relational databases vs Non-relational databasesJames Serra
There is a lot of confusion about the place and purpose of the many recent non-relational database solutions ("NoSQL databases") compared to the relational database solutions that have been around for so many years. In this presentation I will first clarify what exactly these database solutions are, compare them, and discuss the best use cases for each. I'll discuss topics involving OLTP, scaling, data warehousing, polyglot persistence, and the CAP theorem. We will even touch on a new type of database solution called NewSQL. If you are building a new solution it is important to understand all your options so you take the right path to success.
The document discusses various types of physical storage media used in databases, including their characteristics and performance measures. It covers volatile storage like cache and main memory, and non-volatile storage like magnetic disks, flash memory, optical disks, and tape. It describes how magnetic disks work and factors that influence disk performance like seek time, rotational latency, and transfer rate. Optimization techniques for disk block access like file organization and write buffering are also summarized.
This document describes four types of databases: hierarchical, network, relational, and object-oriented. Hierarchical databases organize data in a tree structure with parent-child relationships. Network databases use a many-to-many relationship structure like a graph. Relational databases organize data into tables with rows and columns. Object-oriented databases store reusable software objects that contain data and instructions.
Distributed database management systemsDhani Ahmad
This chapter discusses distributed database management systems (DDBMS). A DDBMS governs storage and processing of logically related data across interconnected computer systems. The chapter covers DDBMS components, levels of data and process distribution, transaction management, and design considerations like data fragmentation, replication, and allocation. Transparency and optimization techniques aim to make the distributed nature transparent to users.
The document discusses deductive databases and how they differ from conventional databases. Deductive databases contain facts and rules that allow implicit facts to be deduced from the stored information. This reduces the amount of storage needed compared to explicitly storing all facts. Deductive databases use logic programming through languages like Datalog to specify rules that define virtual relations. The rules allow new facts to be inferred through an inference engine even if they are not explicitly represented.
The document introduces web services and the .NET framework. It defines a web service as a network-accessible interface that allows applications to communicate over the internet using standard protocols. It describes the key components of a web service including SOAP, WSDL, UDDI, and how they allow services to be described, discovered and accessed over a network in a standardized way. It also provides an overview of the .NET framework and how it supports web services and applications using common languages like C#.
A great power point presentation for DBMS Concepts from start to end and with best examples chapter by chapter. Please go though each chapters sequentially for your knowledge.
A very easy going study material for better understanding and concepts of Database Management System!
This document discusses the conversion of Montgomery County Public Schools' student systems from a legacy IDMS database to an Oracle database. It summarizes the current and planned processes for generating administrative reports, enrollment data for the Department of Reporting and Regulatory Accountability, and data for special education. The administrative reports and enrollment data will initially be generated using a legacy extract uploaded to Oracle tables, before being produced directly from Oracle in the future. Special education data will also transition from the legacy system to Oracle tables and processes.
Top 5 performance and capacity challenges for z/OS Metron
The document discusses top performance and capacity challenges for z/OS, including:
1) Managing z/OS in large enterprises with aging workforces.
2) Planning zIIP capacity as organizations upgrade to newer IBM mainframe models.
3) Tuning WebSphere MQ and bufferpools on z/OS to control performance issues.
The document describes several database models:
- Hierarchical model organizes data in a tree structure and allows records to have repeating information. It was popular from the 1960s-1970s.
- Network model permitted modeling many-to-many relationships and was formally defined in 1971.
- Relational model represents data as tables and allows definition of structures, storage, retrieval and integrity constraints. It is the most commonly implemented model today.
- Object/relational model adds object storage capabilities to the relational model.
In this educational webinar, the heads of mainframe development and product management from Syncsort will discuss key mainframe optimization problems, opportunities and use cases for 2017, spanning DB2 and network management on z/OS, as well as new ways to save on your monthly IBM MLC charges and new options for long-standing mainframe issues.
Watch this webcast on-demand to learn:
o How the latest innovations for zIIP and sort will save you time and money each month
o How workload-centric database optimization changes the game for DB2 and IDMS
o New options for long-standing network management and IMS cost and resource issues
The document discusses a CA IDMS Database Navigation course that focuses on navigating a CA IDMS database using data structures and currency rather than complex programming syntax. The course agenda covers topics like data relationships, storage, set structures, and navigational DML statements. It provides explanations of key CA IDMS concepts to help students learn how to access and update data in a CA IDMS database.
Huffman codes are a technique for lossless data compression that assigns variable-length binary codes to characters, with more frequent characters having shorter codes. The algorithm builds a frequency table of characters then constructs a binary tree to determine optimal codes. Characters are assigned codes based on their path from the root, with left branches representing 0 and right 1. Both encoder and decoder use this tree to translate between binary codes and characters. The tree guarantees unique decoding and optimal compression.
Indexing and hashing are crucial techniques for efficiently finding and accessing data in databases. There are various types of indices such as ordered, hash, dense, sparse, and multilevel indices that each have their own tradeoffs regarding speed, space usage, and ease of updates. B-tree and B+-tree data structures provide fast indexed access while also efficiently handling updates. Hashing techniques like static, dynamic, and extendable hashing map data to buckets through hash functions but require mechanisms like overflow chaining to handle collisions. The most appropriate technique depends on factors like the query types and frequencies of data access, insertion, and deletion.
Artificial neural network model & hidden layers in multilayer artificial neur...Muhammad Ishaq
Artificial neural networks (ANNs) are computational models inspired by biological neural networks. ANNs can process large amounts of inputs to learn from data in a way similar to the human brain. There are different types of ANN architectures including single layer feedforward networks, multilayer feedforward networks, and recurrent networks. ANNs use supervised, unsupervised, or reinforced learning. The backpropagation algorithm is commonly used for training multilayer networks by propagating errors backwards from the output to adjust weights. Developing an ANN application involves collecting data, separating it into training and testing sets, designing the network architecture, initializing parameters/weights, transforming data, training the network using an algorithm like backpropagation, testing performance on new data, and
This document summarizes indexing and hashing techniques for database systems. It describes ordered indices like B-trees that store index entries in sorted order, and hash indices that distribute entries uniformly across buckets. B+-tree index files are introduced as an improvement over indexed-sequential files that automatically reorganizes with small local changes, avoiding the need to periodically reorganize the entire file. The structure and properties of B+-tree nodes and trees are defined.
This document defines and describes several types of databases. It begins by defining a database as an organized collection of digital data. It then explains document-oriented, embedded, graph, hypertext, operational, distributed, and flat-file databases. For each type, it provides a brief definition and examples. The document was created by trainees of Baabtra as part of a mentoring program and provides contact information at the end.
The document discusses R-trees, a data structure used to index multi-dimensional spatial data. R-trees allow for efficient searching of spatial data by grouping data into minimum bounding rectangles (MBRs) and storing them in a tree structure based on these envelopes. The tree structure resembles a B+-tree, with internal nodes containing pointers to child nodes or data records. R-trees provide efficient search, insertion, and deletion of spatial data objects through operations on the tree structure and splitting or merging of nodes as needed.
The document discusses various indexing techniques used to improve data access performance in databases, including ordered indices like B-trees and B+-trees, as well as hashing techniques. It covers the basic concepts, data structures, operations, advantages and disadvantages of each approach. B-trees and B+-trees store index entries in sorted order to support range queries efficiently, while hashing distributes entries uniformly across buckets using a hash function but does not support ranges.
This document discusses different searching methods like sequential, binary, and hashing. It defines searching as finding an element within a list. Sequential search searches lists sequentially until the element is found or the end is reached, with efficiency of O(n) in worst case. Binary search works on sorted arrays by eliminating half of remaining elements at each step, with efficiency of O(log n). Hashing maps keys to table positions using a hash function, allowing searches, inserts and deletes in O(1) time on average. Good hash functions uniformly distribute keys and generate different hashes for similar keys.
This document provides an overview of the network data model and the CODASYL DBTG model for representing data structures in a database. It describes how records, links, and relationships map to entities and relationships in the entity-relationship model. It also explains key concepts of the CODASYL model including data structure diagrams, DBTG sets, and provides examples of how to perform data retrieval, updating, and set processing operations using the DBTG data manipulation language.
This document provides an overview of the basic concepts and components of the CODASYL network model for database design. It describes how data is represented using record types and links, how relationships are modeled, and how data structure diagrams depict the logical structure of a database. It also explains how the CODASYL model maps networks to files using pointers and ring structures, and how the DBTG (Data Base Task Group) implementation facilitates data retrieval, updating, and set processing using commands, program work areas, and currency pointers.
This document provides an overview of the network model for representing data in a database. It describes basic concepts like records and links, how data structure diagrams represent the structure of a database, and the DBTG CODASYL model which uses sets and links to represent relationships. It also summarizes the DBTG facilities for data retrieval, updating records and sets, and ordering sets.
This document describes the network model for representing data and relationships in a database. It discusses how records and links represent entities and relationships. Data structure diagrams are used to represent the schema, and record types and links specify the logical structure. General relationships of degree 3 or higher are represented using a dummy record type. The DBTG CODASYL model represents all links as many-to-one relationships using sets. The DBTG data manipulation language allows querying, updating, and manipulating the database using commands like find, get, store, modify, and erase.
A database management system (or DBMS) is essentially nothing more than a computerized data-keeping system. Users of the system are given facilities to perform several kinds of operations on such a system for either manipulation of the data in the database or the management of the database structure itself.
Purpose of the data base system, data abstraction, data model, data independence, data definition
language, data manipulation language, data base manager, data base administrator, data base users,
overall structure.
ER Models, entities, mapping constrains, keys, E-R diagram, reduction E-R diagrams to tables,
generatio, aggregation, design of an E-R data base scheme.
Oracle RDBMS, architecture, kernel, system global area (SGA), data base writer, log writer, process
monitor, archiver, database files, control files, redo log files, oracle utilities.
SQL: commands and data types, data definition language commands, data manipulation commands,
data query language commands, transaction language control commands, data control language
commands.
Joins, equi-joins, non-equi-joins, self joins, other joins, aggregate functions, math functions, string
functions, group by clause, data function and concepts of null values, sub-querries, views.
PL/SQL, basics of pl/sql, data types, control structures, database access with PL/SQL, data base
connections, transaction management, data base locking, cursor management.
This document provides an overview of database management systems (DBMS). It discusses the history and purpose of DBMS, different data models including relational, entity-relationship and object-oriented models. It also describes database languages, data storage and querying, transaction management, and database architecture. Key topics covered include the three levels of data abstraction, database schemas and instances, storage managers, query processors, and ensuring integrity through constraints defined in the data definition language.
The document provides an overview of databases and their advantages over traditional file systems. It discusses key database concepts like data hierarchy, entities and attributes, database models, and components. The main points are:
- Databases organize related data centrally for efficient data sharing and management, avoiding data duplication found in file systems.
- Key concepts include data hierarchy, database components, architecture with three logical levels, and entity-attribute modeling.
- Popular database models include hierarchical, network, and relational models, with relational being most common today.
- Database languages like DDL and DML manipulate and query the database, while the data dictionary documents the stored data.
Database concepts such as data, information, fields, records, files and database models including flat, hierarchical and network models were discussed. Database architecture including schemas, instances, languages and interfaces were also covered.
A DVD rental database was provided as a real-life example to demonstrate database concepts and architecture.
A short quiz concluded the summary to test understanding of key terms introduced in the document.
The document provides an overview of NoSQL databases and MongoDB. It discusses:
- What NoSQL is and why it was created
- The different categories of NoSQL databases, including key-value stores, document databases, column family stores, and graph databases
- MongoDB specifically, including its flexible schema, horizontal scalability, replication support, and data modeling approach
- Comparisons between relational and NoSQL databases
The document provides an overview of NoSQL and MongoDB. It discusses that NoSQL databases were built for large datasets and cloud applications. It covers some of the main types of NoSQL databases like document stores, key-value stores, and column family stores. The document also compares NoSQL to SQL/relational databases, discussing how NoSQL is more flexible and scales horizontally. MongoDB is presented as a popular document-oriented NoSQL database, covering its flexible schema, horizontal scaling, and replication features.
The document provides an overview of database systems and their components. It discusses:
- The purpose of database systems is to provide solutions to problems with using file systems like data redundancy, difficulty of accessing data, and lack of integrity and security.
- Database systems include a collection of interrelated data, a set of programs to access the data called a database management system (DBMS), and database applications in domains like banking, airlines, education and more.
- Key components of database systems include data models, data definition and manipulation languages, transaction management, storage management, database administrators, and database users. The overall system has physical, logical and view levels of abstraction.
The document discusses hierarchical database models and concepts including:
- Records are organized into a tree structure with parent-child relationships
- Queries can retrieve records by traversing the tree structure using pointers
- The IMS database system was an early commercial hierarchical database that used various access methods like HSAM and HISAM
Introduction to Database, Purpose of Data, Data models, Components of Databasekasthurimukila
This document provides an overview of database management systems and their components. It discusses the purpose of DBMSs in providing data storage and access across applications. It also describes key DBMS concepts like data models, languages for defining and manipulating data, transaction management, storage structure, database administrators, and system users. The relational model and SQL query language are highlighted as widely adopted standards. Overall, the document gives a high-level introduction to DBMS components, data management challenges addressed by DBMSs, and their role in application development.
Dear students get fully solved SMU MBA assignments
Send your semester & Specialization name to our mail id :
“ help.mbaassignments@gmail.com ”
or
Call us at : 08263069601
This document provides an introduction to database management systems (DBMS). It discusses key concepts such as database models including hierarchical, network, relational and entity-relationship models. It also covers database planning, design, implementation and maintenance. Specific topics covered include data modeling, database normalization, query languages, transaction management and database administration.
This document provides information about assignments for the Fall 2014 semester for the B.Sc IT program. It includes the subject code and name, credit hours, and evaluator for the assignment. It then lists 6 questions related to database management systems, including explanations of data independence, SQL server architecture, indexed sequential file organization, the system catalog in RDBMS, semantics of tuple relational calculus queries, and Boyce-Codd normal form with an example. Students are instructed to email their semester and specialization to receive fully solved assignments.
The document provides an overview of database systems and their components. It discusses the purpose of database systems in addressing issues with file-based data storage like data redundancy, integrity problems, and concurrent access. It also describes the major components of a database system including the data models, data definition and manipulation languages, transaction management, storage management, database administrators, and users. The relational and entity-relationship models are explained as examples of common data models.
The document discusses object-relational and extended relational databases. It covers how an ORDBMS supports both relational and object-oriented aspects by allowing objects, classes, inheritance and other OO concepts in database schemas and queries. It provides examples of using ADTs and structured types to store complex data like videos more efficiently compared to a traditional RDBMS. Query processing and optimization techniques for ORDBMS are also discussed, such as user-defined aggregates, method caching and pointer swizzling.
The document provides an overview of database management systems (DBMS). It discusses DBMS applications, why DBMS are used, different users of databases, data models and languages like SQL. It also summarizes key components of a DBMS including data storage, query processing, transaction management and database architecture.
2. Network Model
Another widely used in data model
Many-to-Many relationship
Owner – parent record
Member – child record
Links – collection of records which are connected to
one another
3. Concept of Owner-Member Relationship
DEPARTMENT
FACULTY MAJORS
CLASSES
STUDENTS
OWNER-MEMBER
RELATIONSHIP
4. OCCURRENCE DIAGRAMS
Used to illustrate the distribution of owner and member
records within a network database
Helps in navigation of the database
5. An Occurrence Diagram
Dr. Jao Faculty
BSIT records
Department Dr.
records Ramiro
BSCS
DIT
Faculty Dr.
records
Dr. Flavier Dr. J
Belen Dr.
Cruz
Dr. Dr.
Holmes Rizal
Dr. No
Faculty
records
6. CODASYL-DBTG Model
Conference On Data System Languages, Data Base
Task Group
Original network model presented in a report by
CODASYL-DBTG
Collection of set types, owner record types, and
member record types
7. Characteristics of CODASYL Network Model
1. There must be one-to-many relationship between
pairs of record types related with respect to an
owner-with-member relationship
2. A given owner instance must posses a unique set
of member instances
3. A given record type cannot be both the owner and
member of the same set type
Records and their fields are represented as record type
type customer = record type account = record
customer-name: string; account-number: integer;
customer-street: string; balance: integer;
customer-city: string;
8. DBTG Model
Simplified by limiting the link options to one-to-one or
one-to-many
Entity relationship is referred to as DBTG set
The arrowhead is used to
Segment A
denote: ownership
Records or segments are
represented as boxes
Links are represented as
Segment B
lines
9. DBTG Model
Just like in hierarchical databases, a particular set
can have any number of set occurrences
CUSTOMER A CUSTOMER B CUSTOMER C
ACCOUNT 1 ACCOUNT 2 ACCOUNT 3 ACCOUNT 4 ACCOUNT 5 ACCOUNT 6
A descriptive CUSTACCT SET OCCURRENCES
way of
naming a
DBTG
database is
by
combining
the names of
the owner
and member
segments
10. DBTG Model
Another way of illustrating a set occurrence is similar
to the one used in mathematical sets
CUSTOMER A CUSTOMER B CUSTOMER C CUSTOMER D
ACCOUNT 1 ACCOUNT 4 ACCOUNT 6
ACCOUNT 1 ACCOUNT 5
ACCOUNT 1
CUSTACCT SET OCCURRENCES
11. DBTG Model
A set of occurrence can be represented as a link list
CUSTOMER A ACCOUNT 1 ACCOUNT 2 ACCOUNT 3
CUSTOMER B ACCOUNT 4 ACCOUNT 5
CUSTOMER C ACCOUNT 6
Illustrates
that the
member LINKED REPRESENTATION OF A SET OCCURRENCES
segments
are
ordered
12. DBTG Model
CUSTOMER BRANCH
Let us add
another owner
segment and ACCOUNT
call it BRANCH
This segment
is also an
owner of the
ACCOUNT
segment
13. DBTG Model
The Data Structure Diagram below shows the
inclusion of segment BRANCH and fields of each
segment
CUSTOMER BRANCH
name street city name assets city
ACCOUNT
number balance
14. DBTG Model
A populated representation will help further
understanding the existing owner-member
relationship in set CUSTACCT and BRNACCT
ACCOUNT 1
CUSTOMER ACCOUNT 2 BRANCH 1
A
CUSTOMER ACCOUNT 3
BRANCH 2
B
CUSTOMER ACCOUNT 4
C
ACCOUNT 5
ACCOUNT 6
CUSTACCT AND BRNACCT OWNER-MEMBER RELATIONSHIP
15. DBTG Model
OWNERS MEMBERS
CUSTOMER A ACCOUNT 1, 2 AND 3
CUSTOMER B ACCOUNT 4 AND 5
CUSTOMER C ACCOUNT 6
BRANCH 1 ACCOUNT 1, 2 AND 4
BRANCH 2 ACCOUNT 3, 5 AND 6
SET COMPOSITION SUMMARY
•Segments are owned by more than one owner segment
•This illustrates the fact that entity relationships within a DBTG set is
limited to one –to-one or one-to-many
•This avoids the need to deal with complicated many-to-many
relationships
16. DBTG Model
CUSTOMER SEGMENT BRANCH SEGMENT
NAME ADDRESS CITY NAME ASSETS CITY
Hagar Kalayaan Quezon Grace Park 1000000000 Caloocan
1
Ana Avenida Manila
Cervantes 1233333455 Manila
Carlo Forbes Manila 6
ACCOUNTS SEGMENT
NUMBER BALANCE
12340 1000
12341 100020
12342 10006
12343 123222
12344 21233
12345 123433
SAMPLE RECORDS OF THE THREE SAMPLE SEGMENT
18. DBTG Data-Retrieval Facility
The DBTG data manipulation language consists of a
number of commands that are embedded in a host
language
Run unit
System application program consisting of a sequence of
host language and DBTG command statements
Statements access and manipulate database items as
well as locally declared variables
Program work-area (or user work area)
A buffer storage area the system maintains for each
application program
19. DBTG Variables
Record Templates
Currency pointers
Current of record type
Current of set type
Current of run unit
Status flags
DB-status is most frequently used
Additional variables: DB-set-name, DB-record-name,
and
DB-data-name
20. Example Program Work Area
Templates for three record types:
customer
Account
branch
Six currency pointers
Three pointers for record types: one each tot he most recently
accessed customer, account, and branch record
Two pointers for set types: one to the most recently accessed
record in an occurrence of the set depositor, one to the most
recently accessed record in an occurrence of the set account-
branch
One run-unit pointer
Status flags: four variables defined previously
Following diagram shows an example program work area
state
22. The Find and Get Commands
find
Locates a record in the database and sets the appropriate
currency pointers
get
Copies of the record to which the current of run-unit points from
the database to the appropriate program work area template
Example: Executing a find command to locate the
customer record belonging to Johnson causes the
following changes to occur in the state of the program
work area.
The current of the record type customer now points to the
record of Johnson
The current of set type depositor now points to the set owned
by Johnson
The current of run unit now points to customer record Johnson
23. Access of Individual Records
find any <record type> using <record-field>
Locates a record of type <record type> whose <record-
field>
value is the same as the value of <record-field> in the
<record type> template in the program work area.
Once such a record is found, the following currency
pointers are set to point to that record:
The current of run-unit pointer
The record-type currency pointer for <record type>
For each set in which that record belongs, the appropriate
set currency pointer
find duplicate <record type> using <record-field>
Locates (according to a system-dependent ordering) the
next record that matches the <record-field>
24. Access of Records Within a Set
Other find commands locate records in the DBTG
set that is pointed to by the <set-type> currency
pointer
find first <record type> within <set-type>
Locates the first database record of type <record
type>
belonging to the current <set-type>
find next <record type> within <set-type>
which finds the next element in the set <set-type>
find owner within <set-type>
Locates the owner of a particular DBTG set
25. Predicates
For queries in which a field value must be matched
with a specified range of values, rather than to only
one, we need to:
get the appropriate records into memory
examine each one separately for a match
determine whether each is the; target of our find
statement
26. Example DBTG Query
Print the total number of accounts in the
Perryridge branch with a balance greater than
$10,000
count := 0;
branch.branch-name := “Perryridge”;
find any branch using branch-name;
find first account within account-branch;
while DB-status = 0 do
begin
get account
if account.balance > 10000 then count := count +
1;
find next account within account-branch;
end
print (count);
27. DBTG Update Facility
DBTG mechanisms are available to update
information in the database.
To create a new record of type <record type>
insert the appropriate values in the corresponding
<record type> template
add this new record to the database by executing
store <record type>
Can create and add new records only one at a time
28. DBTG Update Facility
To modify an existing record of type <record type>
find that record in the database
get that record into memory
change the desired fields in the template of <record type>
reflect the changes to the record to which the currency
point of <record type> points by executing
modify <record type>
29. DBTG Update Facility
To delete an existing record of type <record type>
make the currency pointer of that type point to the record in the
database to be deleted
delete that record by executing
erase <record type>
Delete an entire set occurrence by finding the owner of
the set and executing
erase all <record type>
Deletes the owner of the set, as well as all the set’s members.
If a member of the set is an owner of another set, the members
of that second set also will be deleted
erase all is recursive
30. DBTG Set-Processing Facility
Mechanisms are provided for inserting records into
and removing records from a particular set
occurrence
Insert a new record into a set by executing the
connect statement
connect <record type> to <set-type>
Remove a record from a set by executing the
disconnect statement
disconnect <record type> from <set-type>
31. Example disconnect Query
Close account A-201, that is, delete the relationship between
account A-201 and its customer, but archive the record of account A-
201
The following program removes account A-201 from the set
occurrence of type depositor.
The account will still be accessible in the database for record-
keeping purposes
account.account-number := “A-201”;
find for update any account using account-number.
get account,
find owner within depositor,
disconnect account from depositor.
32. DBTG Set-Processing Facility (Cont.)
To move a record of type <record type> from one set
occurrence to another set occurrence of type <set-
type>
Find the appropriate record and the owner of the set
occurrences to which that record is to be moved.
Move the record by executing
reconnect <record type> to <set-type>
Example: Move all accounts of Hayes that are
currently at the Perryridge branch to the Downtown
branch.
33. Example reconnect Query
customer.customer-name := “Hayes”;
find any customer using customer-name;
find first account within depositor;
while DB-status = 0 do
begin
find owner within account-branch;
get branch;
if branch.branch-name = “Perryridge” then
begin
branch.branch-name := “Downtown”;
find any branch using branch-name;
reconnect account to account-branch;
end
find next account within depositor,
end
34. DBTG Set-Processing Facility (Cont.)
A newly created member record of type <record
type> of a set type <set-type> can be added to a set
occurrence either explicitly (manually) or implicitly
(automatically).
Specify the insert mode at set-definition time via
insertion is <insert mode>
manual: connect <record type> to <set-type>
automatic: store <record type>
35. Set Insertion Example
Create account A535 for customer Hayes at the
Downtown branch.
Set insertion is manual for set type depositor and is
automatic for set type account-branch.
branch.branch-name := “Downtown”;
find any branch using branch-name;
account.account-number := “A-535”;
account.balance := 0;
store account;
customer.customer-name := “Hayes”;
find any customer using customer-name;
connect account to depositor;