Database Management System

Seite 1

* Definitions

★ Data: Raw, unprocessed facts

Ex: 25, Suresh, Bangalore

★ Information: Processed data

Ex: The age of Suresh is 25.

★ Database: Collection of related data

Ex: Online banking system, library management system

★ Meta-data: The database definition

* Database Management System

★ Definition: Collection of programs that enables users to create

and maintain the database.

★ Functionalities:

O Define: Specifying the data type, structures and constraints

for the data to be stored.

O Construct: Process of storing data on some storage medium.

O Manipulate: Querying the database to retrieve specific data,

updating database and generating reports.

O Share: Allows multiple users and programs to access the

database concurrently.

* Properties of Database

1. A database represents some aspects of the real world (miniworld).

2. A database is a logically coherent collection of data with some

inherent meaning.

3. A database is designed, built and populated with data for a

specific purpose.

Seite 2

* Characteristics of DBMS Approach

1. Self-Describing Nature of a Database System

* Database system Database + Meta-data (DB Definition)

Stored in: DBMS catalog

Used by: DBMS Software & Database Users

* DBMS software must work equally well with any number of

database applications.

* In traditional file processing, data definition –→ part of

application programs work with only one specific DB.

2. Insulation between Programs and Data, and Data

Abstraction

3. Support of Multiple Views of the Data

4. Sharing of Data and Multiuser Transaction Processing