Data Independence

Data Independence

* data independence fully support in DBMS, 
When a schema at a lower level is changed .
Only the mappings need to be changed  between this schema and higher-level schema(s).

The higher-level schemas themselves are unchanged.

The application programs need not be changed since they refer to the external schemas.

* Logical Data Independence: The capacity to change the conceptual schema without having to change the external schemas and their application programs.

* Physical Data Independence: The capacity to change the internal schema without having to change the conceptual schema.