Data Model

Common Uses of Database Systems• Hotel Reservation• Information on all human genes• The accessories favored by women in 30s.• NIC system

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Traditional File Based Systems

•Collection of application programs and their data.•Each program defines and manages its own data

(data separation).•Similar to manual filing system.•Works well when the number of items is small.•Also fine when the number of items is large but we

have only to store and retrieve.

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Traditional File Based Systems

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Traditional File Based Systems

Copyright 2004, Dr. Manzoor Hashmani 5

Limitations of File Based Systems• Separation and isolation of data• Duplication of data• Data dependence • Definition of data structure is in application code

• Incompatible File Formats

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Database Approach• The Database

• A shared collection of logically related data and its description.

• Separation of data description from application (program-data independence)• Data Dictionary or Meta Data – the data about data• All problems of file based system removed

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File Based v/s Database Approach

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The Database Management System (DBMS)•A software which enables users to define, create,

maintain, and control access to database.•Provides the following• Define database – Data Definition Language (DDL)•Modify data – Data Modification Language (DML)

•Access Control• Security etc

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Components of the DBMS Environment

• Hardware • Software• Data

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