Data Abstraction in DBMS

Data Abstraction : 

A database system is a collection of interrelated files and a set of programs that allow users to access and modify these files. A major purpose of a database system is to provide users with an abstract view of the data. That is, the system hides certain details of how the data are stored and maintained. For the system to be usable, it must retrieve data efficiently. The need for efficiency has led designers to use complex data structures to represent data in the database. Since many database-systems 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: The lowest level of abstraction describes how the data are actually stored. The physical level describes complex low-level data structures in detail.

Logical level: The next-higher level of abstraction describes what data are stored in the database, and what relationships exist among those data. The logical level  thus 
describes the entire database in terms of a small number of relatively simple structures. Although implementation of the simple structures at the logical level may involve
complex physical-level structures, the use of logical level does not need to be aware of this complexity. Database administrators, who must decide what information to keep in the database, use the logical level of abstraction.



View level: The highest level of abstraction describes only part of the entire database. Even though the logical level uses simpler structures, complexity remains because of the
variety of information stored in a large database.Many users of the database system do not need all this information; instead, they need to access only a part of the database. The view level of abstraction exists to simplify their interaction with the system. The system may provide many views for the same database.


Next Topic :

2 comments:

  1. I agree with a lot of the points you made in this article. If you are looking for the DBMS Tutorial, then visit TutorialCup. I appreciate the work you have put into this and hope you continue writing on this subject.

    ReplyDelete
  2. I wanted to thank you for this great Information and knowledge, I definitely loved every little bit of it. I have you bookmarked your web site to check out the latest stuff you post. Your blog is eye-catching. I get pleasure from it. Thanks for sharing this beautiful piece of writing with me, get more information at alteryx certification exam questions for more Analytics Fun related information and knowledge.

    ReplyDelete