Three Levels of Data Abstraction

Question :: Three Levels of Data Abstraction
Answer:
Data abstraction is a process of representing the essential features without
including implementation details.
many database-systems users are not computer trained, developers hide the
complexity from users through several levels of abstraction, to simplify users’
interactions with the system:

1) Physical level.
The lowest level of abstraction describes how the data are
actually stored. The physical level describes complex low-level data
structures in detail.

2) Logical level. 
The next-higher level of abstraction describes what data are
stored in the database, and what relationships exist among those data. The
logical level thus describes the entire database in terms of a small number of
relatively simple structures.

3) View level.

 The highest level of abstraction describes only part of the entire

database. The variety of information stored in a large database. Many users

of the database system do not need all this information; instead, they need

to access only a part of the database. The view level of abstraction exists to

simplify their interaction with the system.