Data independence is the ability to change the schema at one level without affecting the schema at the next higher level.
A database system follows a multilayered architecture. In order to make changes in database without affecting the other data a database system is always designed in multi layers. In database, there are also some database system data which support user data to be locate and retrieve easily and known as meta data.
Meta data always follows multi layer architecture, so that if any changes need to do in a layer, it should not affect the other layers.
What are the types of Data Independence?
- Logical Data Independence
- Physical Data Independence
Logical Data Independence
It stores data about how data will be managed inside a database without having a change in external schema or application program. Also known as Conceptual Schema.
For example – a table definition logic for its constraints in a database.
Physical Data Independence
It has the ability to change the physical data without affecting the logical data or external schema. Also, knows as Internal Schema.
For example – Upgrading the storage system, file organization, storage structure.