- In this lecture the concept of Data Independence has been explained.
- Data Independence: Capacity of changing some part of schema without affecting entire schema either by deleting old database or creating new database.
- 3 levels of schema are:
- Application Schema: application programs run at this level
- Logical/Conceptual Schema: relationship exists
- Physical Schema: Storage level
- Logical Data Independence: Capacity of changing conceptual level /logic without affecting application program
- Physical Data Independence: Capacity of changing physical schema without affecting logical schema.