- Introduction to Data Independence
- Types of Data Independence
Introduction to Data Independence
Data independence The ability to modify schema definition in a level, without the schema definition in the next level, is called data independence.
There are two types of data independence.
1.Logical data independence
2.Physical data independence
logical data independence
Replace without external schema (change level) to change the logical schema (conceptual level) is called logical data independence.
For example – it is possible to add or remove attributes, new entities for conceptual schema, without making changes in the external schema.
physical data independence
Changing the physical schema without making changes in the logical schema is called physical data independence.