Database Concept

What is data?
Row facts and Figure.

Collection of information  in organized manner is called database

DBMS:Database Management Syastem
is a program that stors,retrives and motifies data in the database on request.

Types of database:
1)Hierachical
2)Network
3)Relational
4)Object relational

E_R Diagram

Entity:A group of real thing

DBMS: examples Msexcel,MS Access

RDMS
1970- by Dr.E.F Codd
Some Rules
Oracle follows 11.2 Rules

Four Rules:-
1.Data must be accessible.
2.Data must be in Tabular Form.
3.There must be relationship between rows and coloumns.
4.There are some rules and operation to maintain there relationship.

Types of Relatioinships
1.One to One
2.One to many
3.Many to Many.