Tuesday 25 February 2014

Data Independence |Introduction to Database management system


DEFINITION-
Data independence means upper layers are unaffected by any change in the lower layers.

TYPES OF DATA INDEPENDENCE-
There are 2 types of data independence.
1. LOGICAL DATA INDEPENDENCE
2. PHYSICAL DATA INDEPENDENCE

1. LOGICAL DATA INDEPENDENCE- If conceptual level changes no effect on external level.

2. PHYSICAL DATA INDEPENDENCE-If Internal level changes no effect on conceptual level.


 (3 LEVEL ARCHITECTURE)

0 comments:

Post a Comment