Database is an organised collection of data or information so that it can be easily accessed, updated or manipulated. Database management system (DBMS) is a software that manages database on a computer. Eg. microsoft access, MySQL, oracle etc. Database are classified according to their organisational approach. Few of them are listed below : Relational database :- A tabular database in which data is defined so that it can be reorganized and accessed in a number of different ways. It stores data in tables with relationships to other tables. Distributed database :- A distributed database is one that can be dispersed or replicated among different point in a network. Object oriented programming database :- In this database, the data is defined in object classes and sub classes. MySQL, a popular DBMS used online is an example of object oriented DBMS.