Data Base Management System

1. Data Base Management System

3. Data
• Data is a collection of raw facts.
• It is a collection of known facts , figures or statistics that
can be recorded.
• It can be text, numbers, audio, video or any combination
of these.
Ex: Reg.no, Name, Class, Address, Phone no & etc…

4. Database
• A database is integral collection of logically related records
and files.
• A Database is a structured set of data held in a computer,
especially one that is accessible in various ways.
• It is a collection of related data, having valid and implicit
meaning and is designed to meet the information needs of
the organization.
• Ex: A college staff database contains data regarding name,
date of joining, basic salary, net salary, DA, HRA & etc..

5. Implicit Properties of Database
• A database is a logically coherent collection of data with
some inherent meaning.
• A database is designed, built and populated with data for
a specific purpose.
• A database can be of any size and any level of complexity.
• A database may be generated and maintained manually
or a group of application programs written specifically for
the task or by DBMS.

6. Types of Database
1. Database for End-user – Each workstation is like a small database in itself which includes data
in spreadsheet, presentations, word files, notepads & etc..
2. Operational Databases- This database is usually huge important to organizations as they
include the customer database , personal database and inventory database. The data stored
in operational databases can be changed and manipulated depending on what the company
requires.
3. Database Warehouse – Organizations are required to keep all relevant data for several years.
This data is also an important source of information for analyzing and comparing the current
year data with that of the past years which also makes it easier to determine key trends
taking place.
4. Distributed Database – Many organizations have several office locations, manufacturing plants
, regional offices , branch offices and a head office at different geographical locations. Each
of these work groups may have their own database which together will form the main
database of the company. This is known as distributed database.
5. Relational Database – In this, the data in a relational database is stored in various data tables.
This is the most common of all the different types of databases. Each table has a key field
which is used to connect it to other tables. Hence all the tables are related to each other
through several key fields.

7. Implication of database approach
i)Potential for Enforcing standards - Database approach permits DBA to define and enforce standards
among database users in a large organization. Typically standards can be defined for the following,
-Names & format of the data elements, display format, Report structures & etc..
ii)Reduced Application Development Time - Developing new application such as retrieval of certain
specific data from the database or generating and printing a new report is less time consuming in
DBMS approach .
iii)Flexibility - DBMS must be flexible to accept any structural changes. If the end user needs change,
accordingly the database has to be changed to meet the needs of the user.
iv)Availability of Up-to-date Information – Since a number of users are using the DBMS simultaneously , it
is necessary that updation made by one user must be immediately seen by the other users also.

8. Database System
• A database system is a collection of related
data stored in a well-organized manner. This
system ensures that the data is simplified,
secure and easy to access.
• A DBMS is a software that allows creation,
definition and manipulation of database,
allowing users to store, process and analyze
data easily. DBMS provides us with an
interface or a tool, to perform various
operations like creating database, storing
data in it, updating data, creating tables in
the database and a lot more.
• DBMS also provides protection and security
to the databases. It also maintains data
consistency in case of multiple users.

9. Purpose of Database systems
• Data redundancy and inconsistency .
• Difficulty in accessing data.
• Data isolation-multiple files and formats.
• Integrity problems.
• Atomicity of updates.
• Concurrent access by multiple users.
• Security problems.

10. Objectives of Database system
 Availability
 Bulk Data
 As per the requirement
 Adaptability
 Integrity
 Data Independence – Physical & logical data
independence
 Share ability.

11. Database System Applications
1.Banking
2.Airlines
3.Universities
4.Credit card transactions
5.Telecommunication
6.Finance
7.Sales
8.Manufacturing
9.Human resources

12. Database Language
1.DDL(Data Definition Language)-DDL is used for specifying
the database schema. It is used for creating tables,
schema, indexes, constraints etc. in database.
2.DML(Data Manipulation Language)-DML is used for
accessing and manipulating data in a database.
3.VDL(View Definition Language)- Represents user views
and their mapping to the conceptual schema.
4.SDL(Stored Definition Language)-Specifies the mapping
between two schemas.

13. Database Administrator(DBA)
An IT professional responsible for the installation, configuration,upgrading,monitoring
maintenance and security of database in a organization is called database
administrator(DBA).
Role of DBA
1.The development of database strategies.
2.To design of database strategies.
3.To provide system monitoring.
4.To improve database performance.
5.Enhancing capacity.
6.Planning for future expansion requirements.
7.To implement security measures to safeguard the database.

14. Database Users
1.Database Administrators.
2.Database designers
3.End users
-Casual end users
-Naïve or parametric end users
- Sophisticated end users
-Stand alone users
4.System Analysts and Programmers

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• 1.DBA
• 2.Database designer- It identifies data to be stored in the database
and choosing appropriate structures to represent and stored the
data. It is the responsibility of the designers to communicate with all
users to understand their requirements. It interact with all potential
users and develop views of the database that meet the data and
processing requirements of these groups.
• 4.System Analyst and Programmer – They determine end user
requirements and develop specifications for canned transactions that
meet the requirements. The application programmers implement the
specifications as programs, then test and debug the programs.

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3.End users
• Casual end user – They occasionally access, may need different
information each time.
• Naïve end user-The main job is to query and update the database
using standard queries and updates.
• Sophisticated end user-They include engineers, scientists , analyst
who implement applications to meet their requirements.
• Standalone end user-They maintain personal database using
readymade packages.

17. Transaction Management
• A Transaction is an execution of a program that specifies certain
properties like Atomicity, Consistency, Isolation & Durability(ACID).
• A Transaction is an atomic unit.
• A database transaction must be atomic, meaning that it must be
either entirely completed or aborted.
• A database system will guarantee the properties of ACID for each
transaction.
• A transaction can be defined as a group of tasks and activities .
• A single task is the minimum processing unit. This cannot be divided
further into smaller parts.

18. ACID Properties
A transaction is a very small unit of a program and it consists of many low level tasks. It
is a transaction in database system.
Atomicity – This property states that a transaction must be treated as an atomic
unit.This means that either its operations are executed or none are executed .
Consistency – The database must remain in a consistent state after any transaction has
been done . No transaction should have any adverse effect on the data residing in
the database.
Durability – The database should be durable enough to hold all its latest updates even
if the system fails.If a transaction updates a chunk of data in a database,then the
database will hold the modified data.If a transaction commits but the system fails
before the data could be written on to the disk,then that data will be updated once
the system springs back into action.
Isolation – In a database system where more than one transaction are being executed
simultaneously, the property of isolation states that all the transactions will be
carried out and executed as if it is the only transaction in the system.

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• Serializability – When there are multiple transactions that are being
executed by the operating system in a multi programming
environment , there are possibilities that instructions of one
transaction are interleaved with some other transactions.
• Schedule – it is chronological execution sequence of a transaction .
It is called schedule.
• Serial Schedule – It is a schedule in which transactions are aligned in
such a way that one transaction is executed first. When the first
transaction completes its full cycle , then the next transaction is
executed. Transactions are ordered and done one after the other.
This type of schedule called a serial schedule.

20. Storage Management
• Storage Management is a process in which the processes organizations use to maximize or improve
the performance of their data storage resources.
• It mainly includes virtualization , replication, mirroring, security , compression ,traffic analysis ,
process automation, storage provisioning and all other related techniques.
• It is also simplify the management of storage networks and devices.
• It’s techniques make it possible to reassign storage capacity quickly as business needs change ,
reducing wasted space and improving a company’s ability to respond to evolving market conditions.
• It is closely related to Storage Resource Management (SRM).
• It is closely associated with networked storage solutions such as SAN(Storage area Network) and
NAS(Network-attacked storage) device.
• Various storage management solutions are used by organizations in order to reduce some of those
costs and improve the capabilities and security of their storage solutions.

21. Types of storage
1.Primary Memory – It is also called as main , volatile or temporary
memory. It is directly communicates with CPU. Here the
information will be loss if power supply goes off. It’s storage is very
small and fast .Ex-RAM(Random Access Memory).
2.Secondary Memory – It is also called as Non volatile or permanent
memory. It is not able to communicates with CPU directly. It is used
to store data for future use. Ex- DVD, CD-ROM, Floppy Disk.
3.Tertiary Memory – It is used to store huge volumes of data. Since
such storage devices are external to the computer system, they are
slowest in speed. These storage devices are mostly used to take the
backup of an entire system. Ex- Magnetic tape & optical disk.

22. Features of storage management
1. Volatility
2. Mutability – Read/write storage, read only storage, Slow
write, fast read storage.
3. Accessibility – Random access , sequential access
4. Addressability – Location addressable, File addressable,
content addressable.
5. Capacity – Raw capacity, Memory storage
6. Performance – Latency , Throughput, Granularity, Reliability.
7. Energy Use
Unit – 4 completed