Data Abstraction in DBMS

 

Data Abstraction in DBMS

Hiding Database Design complexities from users (which are not computer professionals) is nothing but known as Data Abstraction.

·        Data Abstraction feature provide easy way to retrieve data, from database.

·        There are three levels of abstraction. 

        Physical level Abstraction

·        Hiding the detail about “how the data is stored actually and where it is stored in database” from user is known as physical level abstraction.

·        The physical level describes complex low-level data structures in detail.

        Logical level Abstraction

·        Hiding the detail about “what data are stored in the database, and what relationships exist among those data” from user is known as logical level abstraction.

·        The logical level describes simple data structures in detail.

     View level Abstraction

·        The view level of abstraction exists to simplify their interaction with the system. The system may provide many views for the same database, may they need to access only a part of the database.

·        Views can also hide information (e.g., salary in emp table) for security purposes.