Process of transforming requests and results between the three levels is called ______________

Ability to modify a schema definition in one level without affecting a schema definition in the next higher level is called ________

___________ is the ability to modify the physical schema without requiring any change in logical (conceptual) schema and application programs

Modifications at the internal levels are occasionally necessary to _____________

_____________ is the ability to modify the conceptual schema without requiring any change in application programs.

Modification at the logical levels is necessary whenever __________________________

The collection of information stored in the database at particular moment is called instance.

Instances are changed frequently.

The overall design of database is called database schema.

Schemas are changed frequently.