Database Management System - DBMS

 

The DBMS is software designed to manage and maintain the database of an organization.  The main steps are data structuring, defining, interrogating, updating and creating. Through these steps, it manipulates the data and provides an environment which is appropriate to use in retrieving and storing the database information.

 

The DBMS is a collection of the inter-related files and a set of programmes through which the users can access and modify these files. In DBMS files contains tables.

 

Data store:  The data are stored in a database in a particular manner. The user of the database need not know how the data are actually stored. For example, if the quality control manager wants the vendor quality rating and the reliability index of the selected vendors, then he can get this report without bothering where and how it is stored in the database. The DBMS will locate them, assemble them and show them in a report format for the user.

 

Data definition and data directory: Since the data independence is provided to the user, it requires that all the users understand the data to the user, it requires that all the users understand the data in the same manner. Therefore, each data entity is defined in the system and its directory is formed for all the users.

 

Interrogation: In interrogation, the data are selected from the database and extracted or copied for processing.  For interrogation, it is necessary to identify the data or a part of the data and the through the user of query language the information is processed and printed.

 

Updating: The database needs updating as the values of the data keep changing from time to time. For updating the database the following information is necessary.

 

§         Description of data

§         Present value of data

§         Changed value of data

§         Processing rule for update

 

Creation: Initially, the database is to be created in the manner and the kind as defined in the DBMS. The data is entered in the database by the transaction processing. A special programme is written to create the database.  The DBMS organize the data internally in the structure defined in the DBMS.