It is difficult to work with the variety and complexity of data at this level.The Physical Data Level is below.
The internal level describes details of how data is stored.There is a random access disk system.It describes the record layout and type of files.
The early applications only dealt with the internal details.It is possible to minimize physical distances between related data and organize the data structures within the file.
When the conceptual level is implemented to a particular database architecture, it is referred to as the Logical level.
Entity-Relationship Modeling is database architecture independent and will be used to abstract the logical view.
The data can be seen in terms of the conceptual level.It is designed for a specific group of users.Portions of stored data should not be seen by some users, and a level of security should be implemented to simplify the view for these users.
Information that can be derived from stored data might be viewed in a similar way.
The applications are written in a foreign language.When accessed, the external view is computed.It isn’t stored.Different categories of users can be provided with different external schemas.At run time, the translation from external level to conceptual level is done by the DBMS.Changes can be made without changing application.