Views of Data

A major purpose of DBMS is to provide users with an abstract view of the data. There are 3 levels of abstraction.

1. Physical Level: Describes how the data are actually stored (complex low-level data structures in detail)
   e.g. customer, account, employee record
2. Logical View: Describes what data are stored in database and relationships.
   e.g. data type of data
3. View Level: Describes only part of entire database.
   e.g. application programs to display data