Data Independence

With knowledge about the three-schemes architecture the term data independence can be explained as followed: Each higher level of the data architecture is immune to changes of the next lower level of the architecture.

Physical Independence:

Therefore, the logical scheme may stay unchanged even though the storage space or type of some data is changed for reasons of optimisation or reorganisation.

Logical Independence:

Also the external scheme may stay unchanged for most changes of the logical scheme. This is especially desirable as in this case the application software does not need to be modified or newly translated.