A major feature of a database system is to provide users with an abstract view of data i.e. the system hides certain details of how data is stored and maintained.
1) Data AbstractionData abstraction is the property of showing only the necessary details to a user and hides the rest of the details from that user. Since many database system users are not computer trained, developers hide the complexity from users through several levels of abstraction, to simplify user’s interactions with the system.
- Physical level – This level describes how data is actually stored in the database.
- Logical level — This level what data are stored in the database and what relationship exist among those data.