Functions of DBMS

Functions of DBMS: 

DBMS performs several important functions that guarantee the integrity and consistency of the data in the database. The most important functions of Database Management System are:

1.      Data Dictionary Management:

DBMS stores definitions of the data elements and their relationships (metadata) in a data dictionary. The DBMS uses the data dictionary to look up the required data component structures and relationships which relieves you from coding such complex relationships in each program. Additionally, any changes made in a database structure are automatically recorded in the data dictionary, thereby freeing you from having to modify all of the programs that access the changed structure.

2.      Data Storage Management:

The DBMS creates and manages the complex structures required for data storage, thus relieving you from the difficult task of defining and programming the physical data characteristics. It provides a mechanism for management of permanent storage of the data. The internal schema defines how the data should be stored by the storage management mechanism and the storage manager interfaces with the operating system to access the physical storage.

3.      Data Transformation and Presentation:

The DBMS transforms entered data in to required data structures. By using the data transformation and presentation function the DBMS can determine the difference between logical and physical data formats. That is, the DBMS formats the physically retrieved data to make it conform to the user’s logical expectations.

For example, imagine an enterprise database used by a multinational company. An end user in England would expect to enter data such as July 11, 2009, as “11/07/2009.” In contrast, the same date would be entered in the United States as “07/11/2009.” Regardless of the data presentation format, the DBMS system must manage the date in the proper format for each country.

4.      Security Management:

Security Management is another important function of the Database Management System. The DBMS creates a security system that enforces user security and data privacy. Security rules determine which users can access the database, which data items each user can access, and which data operations (read, add, delete, or modify) the user can perform. This is especially important in multiuser database systems.

5.      Multiuser Access Control:

To provide data integrity and data consistency, the DBMS uses sophisticated algorithms to ensure that multiple users can access the database concurrently without compromising the integrity of the database. Multiuser access control is a very useful tool in a DBMS, it enables multiple users to access the database simultaneously without affecting the integrity of the database.

6.      Backup and Recovery Management

The DBMS provides backup and data recovery to ensure data safety and integrity. Current DBMS systems provide special utilities that allow the DBA to perform routine and special backup and restore procedures.

Recovery management deals with the recovery of the database after a failure, such as a bad sector in the disk or a power failure. Such capability is critical to preserving the database’s integrity.

7.      Data Integrity Management

The DBMS promotes and enforces integrity rules, thus minimizing data redundancy and maximizing data consistency. The data relationships stored in the data dictionary are used to enforce data integrity. Ensuring data integrity is especially important in transaction-oriented database systems.

8.      Database Access Languages and Application Programming Interfaces:

The DBMS provides data access through a query language. A query language is a non-procedural language—one that lets the user specify what must be done without having to specify how it is to be done. Structured Query Language (SQL) is the default query language and data access standard supported by the majority of DBMS vendors.

9.      Database Communication interfaces:

This refers to how a DBMS can accept different end user requests through different network environments. For example, the DBMS might provide access to the database via the Internet through the use of Web browsers such as Mozilla Firefox or Microsoft Internet Explorer. In this environment, communications can be accomplished in several ways.


-profshardulp.patil@gmail.com