2) File- based approach vs database approach

File-based system

A collection of application programs that perform services for the end users.

Database

A collection of shared logically related data, stored in automated form and designed to meet the information needs of an organisation.

DBMS

A software package that enables users to define, create, manage and maintain the database.

Disadvantages of file-based systems (D.D.F.S)

D) Data dependency on a programming language and incompatible file formats. D) Duplication of data - the same data can be held by different programs. F) Fixed queries - new requirements require new program. S) Separation of data - users of one program may be unaware of potentially useful information in another program.

Database users

Database designers Database adminstrators Data adminstrators Application developers End users

Database disadvantages

Training Cost Not suitable for small scale projects

DML

Used for accessing and manipulating stored data.

DDL

Used for defining a database's data types, data structures and constraints.

DBMS Features (V.C.R.S)

V) Views C) Concurrent access to data R) Recovery and back up S) Security and integrity