* 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.