What do you understand by degrees of Data Abstraction?
Solution
While designing database we should start with abstract view of data environment and insert
details as implementation comes closer.Degress of data abstraction will help in implementing
different view of data.
There 4 Levels of degrees of Data Abstraction:
A}The External Model :It is available for end user.End user means people who use database
application and modify data.
B)The Conceptual Model:It considers all views of database and creates global view of
database.It is represented using ER diagram.
C)The Internal Model:It is formed after selection of database platform.It maps Conceptual Model
to DBMS.It represents databse as seen by DBMS.It will to acheive logical independence. logical
independence means changing internal model without affecting Conceptual Model.
D)The Physical Model This is last and lowest layer of abstraction.It represents how data is stored
in data disk or tapes.It depends on software and hardware.It allows to change Physical Model
without affecting Internal Model.It is called physical independence..
What do you understand by degrees of Data AbstractionSolution.pdf
1. What do you understand by degrees of Data Abstraction?
Solution
While designing database we should start with abstract view of data environment and insert
details as implementation comes closer.Degress of data abstraction will help in implementing
different view of data.
There 4 Levels of degrees of Data Abstraction:
A}The External Model :It is available for end user.End user means people who use database
application and modify data.
B)The Conceptual Model:It considers all views of database and creates global view of
database.It is represented using ER diagram.
C)The Internal Model:It is formed after selection of database platform.It maps Conceptual Model
to DBMS.It represents databse as seen by DBMS.It will to acheive logical independence. logical
independence means changing internal model without affecting Conceptual Model.
D)The Physical Model This is last and lowest layer of abstraction.It represents how data is stored
in data disk or tapes.It depends on software and hardware.It allows to change Physical Model
without affecting Internal Model.It is called physical independence.
