Data Abstraction
Database systems are made up of complex data structures. To ease the user interaction with the database, the developers hide internal irrelevant details from users. This process of hiding irrelevant details from users is called Data abstraction.
There are three level's of abstraction
Physical level: This is the lowest level of data abstraction. It describes how data is actually stored in a database. You can get the complex data structure details at this level.
- The physical level is the bottom level of the abstraction levels.
- This level tells us how the data is stored in the database
Logical level: This is the middle level of 3-level data abstraction architecture. It describes what data is stored in a database.
- The logical level is commonly called the conceptual level point.
- The bottom level of abstraction is the physical level and the next one is the logical level point logical level is just above the physical level point
- This level tells us that what data is stored in the database. This level also tells us what is the relationship that exists among all of the data. The relationship can be one to one, one to many, and many to many, etc.
View level: The highest level of data abstraction. This level describes the user interaction with the database system.
- The bottom level of the abstraction is the physical level. The next higher level is the logical level. The topmost level is the View level.
- This level is specially designed for the end-user.
- The end-user can only access the view level.