Explain the three levels in data abstraction.
Explain the three levels in data abstraction.
Three levels of data abstraction are:
1. Physical level : How the data is stored physically and where it is stored in database.
2. Logical level: What information or data is stored in the database (like what is the data type or what is format of data.
3. View level: End users work on view level. If any amendment is made it can be saved by other name.
For the database to be usable it must retrieve data efficiently. This efficiency led designer to use complex data structure in the database.