Components of Database Management System (DBMS)

Published: 02nd December 2011
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Database management system (DBMS) software is usually developed by commercial vendors and the components of a particular DBMS vary from vendor to another. Some of these components are typically used by specialists of information system for example: information system specialists typically data dictionary/directory, data languages; teleprocessing monitor, application development systems, security software, and archiving and recovery system components of database management system. Other components such a writer and query languages may be used both by programmers and by other non-specialists.

Data Dictionary/Directory: A data dictionary contains the names and descriptions of every data element in the database. It also contains a description of how data element relate to one another. Through the use of its data dictionary, a DBMS stores data in a consistent manner, thus reducing redundancy. The data dictionary also enforces consistency among users and application developers. Application developers use the data dictionary to create the records they need for the programs they are developing. The data dictionary checks records that are being developed against the records that already exist in the database and prevent inconsistencies in data element names and characteristics from occurring. Because of the data dictionary, an application program does not have to specify the characteristics of the data it wants from the database. It merely requests the data from the DBMS. This may permit the user to change the characteristic of a data element in the data dictionary without having to change all the application programs that use the data element.

Data Language: To place a data element in the dictionary, special language is used to describe the characteristics of the data element. This language is called the data description language, or DDL. To ensure the uniformity in accessing data from the database, a DBMS requires standards commands to be used in application programs. These commands are the part of a special language used by programmers to retrieve and process data from the database. This language is called the data manipulation language, or DML. A data manipulation language usually consists of a series of commands, such as FIND, GET. and INSERT. These commands are placed in an application program needs at the right time.

Teleprocessing Monitor: A teleprocessing monitor is a communication software package that manages communications between the database and remote terminals. Teleprocessing monitors often handle order entry systems that have terminals located at remote sales locations. Teleprocessing monitors may be developed by database management system software firms and offered as companion packages to their database products.

Application Development System: An application development system is a set of programs designed to help programmers in developing the application programs that use the database.

Security Software: A security software package provides a variety of tools to shield the database from unauthorized access.

Archiving and Recovery Systems: Archiving programs provide the database manager with tools to make copies of the database, which can be used in case if original database records are damaged. Restart/recovery systems are tools used to restart the database and to recover lost data in the event of a failure.

Report Writers: A report writer allows programmers and other users to design output reports without writing an application program in a programming language, such as COBOL.

Query Languages: A query language is a set of commands for Creating, updating, and accessing data from a database. Query language allows programmers and other users to ask ad hoc questions of the database interactively without the aid of programmers.

Query languages allow users to retrieve data from databases without having detailed information about the structure of records and without being concerned about the process of the DBMS uses to retrieve data.


Rashid Javed writes articles about computer basics such as Information System (IS) Development Process and Management Information System (MIS).

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