LEVELS OF DATA ABSTRACTION in DBMS

LEVELS OF DATA ABSTRACTION

Physical Level DATA  ABSTRACTION
Conceptual DATA  ABSTRACTION
Logical Level DATA  ABSTRACTION

LEVELS OF DATA ABSTRACTION

 This is also called as 'The Three-Schema Architecture’, which can be used to separate the user applications and the physical database.

 

1.Physical Level:

This is a lowest level, which describes how the data is actually stores.

Example:  

Customer account database can be described.

 

2.Logical Level:

This is next higher level that describes what data and what relationships in the database. 

Example: 

 Each record  type customer = record cust_name: sting; cust_city: string; cust_street: string;

end;

3.Conceptual (view) Level:

This is a lowest level, which describes entire database.

Example: 

All application programs.