Data Independence in DBMS

Database architecture is generally designed in different layers so that each layer can work separately and if changes required at any level or at any layer than no problem would be encountered due to separation between the Layers. This separation provides the Data Independence. As we Learnt the Architecture of DBMS where three layers are used View level, Logical Level and Physical Level.

Data Independence means, if changes required at any level or at any schema than no other layers or schema will be infected by changes. The separation or isolation is required from application layer because no need to show the structure of database or its storage.   

Data Independence

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Types of Data Independence

1. Logical Data Independence- It provide the ability to DBMS system that if any changes required at the Logical Schema or Logical Level than do no need to change the application program or view level. It means the External level or application program do not need to modify itself if changes done at logical level. In other words we can say the changes done at logical level will not generate any problem at external level due to the logical data independence. Example changes done in table will not required to modify the view for viewer at view level or External Level.

Logical Data Independence

2. Physical Data Independence- It provide the ability to DBMS system that if any changes required at the Physical Level or Physical Schema than do no need to change the Logical Schema or Logical Level. It means Conceptual Level or Logical Level do not need to change itself if changes done at Physical Level or Physical schema. In other words e can say that the changes done at physical level like storage structure modification, index modification, changes in accessing methods, changes in data structures etc. will not generate any problem at Logical Level de to the Physical Data Independence.   

Physical Data Independence