Data abstraction is a process of hiding the implement details (such as how the data are stored and maintained) and representing only the essential features to simplify user's interaction with the system.
The major purpose of a database system is to provide users with an abstract view of the system.
LEVELS OF ABSTRACTION
To simplify user's interaction with the system, the complexity is hidden from the database users through several levels of abstraction.
Physical Level:
- Lowest level of abstraction.
- Describes how the data are stored.
- Complex low-level data structures described in detail.
- E.g: index, B-tree, hashing.
Logical / Conceptual Level:
- Next highest level of abstraction.
- Describes what data are stored and what relationships exit among those data.
- Database administrator level.
View Level:
- Highest level of abstraction.
- Describes only part of the database for a particular group of users.
- Can be many different views of a database.
