Introduction to Database, Characteristics, Actor on/behind the scenes and Advantages of DBMS approach.

 What is Database? 

A database is a collection of related data. Here Data means known facts that can be recorded and have implicit meaning. for ex: Name, telephone number and address.

Database has a following implicit properties:

• Database represents some aspect of real world.
• Database is a coherent collection of related data with some inherent meaning.
• Database is designed, built and populated with data for specific purpose.
• database can be of any size and complexity.

A database management system (DBMS) is a collection of programs that enables user to create and maintain the database. The DBMS facilitates the process of defining, constructing, manipulating and sharing the databases among various users and applications.

There are several different types of database models have been developed so far, for example, flat, hierarchical, network and relational. These models describe the operations that can be performed on them as well as the structure of the conforming databases. Normally there is a database schema which describes the exact model, entity types, and relationships among those entities.

 Flat Databases have the following characteristics −

• simple
• long and dominant
• useful for very small scale and simple applications.

Relational Databases have the following characteristics.

• Self-describing nature of database system.
• Insulation between programs and data and data abstraction.
• Support multiple views of data.
• sharing of data and multiuser transaction processing.

Actors on the scenes are as follows:

• Database Administrator (DBA)
• Database Designer
• End users - Casual, Parametric, Sophisticated, Standalone.
• System analyst and application programmers.

Workers behind the scenes are as follows:

• DBMS designer and implementor.
• Tool developers
• operator and maintenance personnel.

Advantages of using DBMS approach:

• Controlling redundancy
• restricting unauthorized access.
• providing persistent storage for program objects.
• Providing storage structure for efficient query processing.
• providing backup, recovery, multiple user interfaces.
• enforcing integrity.