Basic Architecture of DBMS | Database Management System

Basic Architecture of DBMS | Database Management System

Basic Architecture of DBMS: A DBMS Centralized the storage and management of data. The purpose of database is to provide correct data to the Correct user at Correct time. The same set of data may be viewed differently by different user, in order to achieve this abstraction is used. Abstraction is the process of showing only necessary details and hiding the rest. The design of database also moves around this concept.

Most of the database Systems are designed around 3-Level/3-Tier architecture. Under this Scheme the database is assumed to be made up of 3 layers or levels and each level is developed accordingly. Each level implements abstraction is some manner.

The following figure illustrates the three level architecture of DBMS:

 

  1. Internal/Physical level: This is the lowest level of abstraction and describes how the data are actually Stored. The physical level describes complex low-level structures in details.
  2. Conceptual/logical level: This is the next-higher level of abstraction and it describes what data items are stored in the database, and what relationship exist among the data. The logical level thus describes the entire database in terms of a small picture of relatively simple structures.
  3. External / View level: This is 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. The system may provide many views for the Same database.