Question

Data independence means

Answer 1

In a database usually there are layers or tiers of management of data.  The data is organized physically on a disk.  Then it is organized by the operating system.  The at application level the data is organized by the user. The data base is defined using schema and a structure.

The actual organization of the data at a lower lever does not affect the data modification, access, structure, definition and organization of data at a higher level, for the user.  User does not have to know about the way data is organized below his/her application level.

this is data independence..