View of Data
The major purpose of the DBMS is to provide users with an abstract view of the data, which hides the details of how the system stores and maintains the data.
Data Abstraction
- Physical level
This describes where the data physically resides and the specifics of how the data is stored.
- Logical level
This the schema of the database, describes the data and its relationships
- View level
This level describes the data that is presented to the user and can present only a portion of a database, or can be a composite from more than one database.
Data Independence
The DBMS uses data independence to decouple the schema from the physical storage. This allows changes to the order that data is stored physically without having to modify the schema and the views of that database.
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