LEVELS OF ABSTRACTION IN A DBMS

LEVELS OF ABSTRACTION IN A DBMS:

 Hiding certain details of how the data are stored and maintained. A major purpose of database system is to provide users with an “Abstract View” of the data. In DBMS there are 3 levels of data abstraction. The goal of the abstraction in the DBMS is to separate the users request and the physical storage of data in the database.

 Levels of Abstraction:

•  Physical Level:

1.     The lowest Level of Abstraction describes “How” the data are actually stored.
2.     The physical level describes complex low level data structures in detail. 

• Logical Level:

1.   This level of data Abstraction describes “What” data are to be stored in the database and what relationships exist among those data.
2.  Database Administrators use the logical level of abstraction. 

• View Level:

1.  It is the highest level of data Abstracts that describes only part of entire database.
2.  Different users require different types of data elements from each database.
3.  The system may provide many views for the some database.