Monday, 3 February 2014


Components of DBMS

A database management system (DBMS) consists of several components. Each component plays very important role in the database management system environment. The major components of database management system are:
  • Software
  • Hardware
  • Data
  • Procedures
  • Database Access Language
Software
The main component of a DBMS is the software. It is the set of programs used to handle the database and to control and manage the overall computerized database
  1. DBMS software itself, is the most important software component in the overall system
  2. Operating system including network software being used in network, to share the data of database among multiple users.
  3. Application programs developed in programming languages such as C++, Visual Basic that are used to to access database in database management system. Each program contains statements that request the DBMS to perform operation on database. The operations may include retrieving, updating, deleting data etc . The application program may be conventional or online  workstations or terminals.
Hardware
Hardware consists of a set of physical electronic devices such as computers (together with associated I/O devices like disk drives), storage devices, I/O channels, electromechanical devices that make interface between computers and the real world systems etc, and so on. It is impossible to implement the DBMS without the hardware devices, In a network, a powerful computer with high data processing speed and a storage device with large storage capacity is required as database server.
Data
Data is the most important component of the DBMS. The main purpose of DBMS is to process the data. In DBMS, databases are defined, constructed and then data is stored, updated and retrieved to and from the databases. The database contains both the actual (or operational) data and the metadata (data about data or description about data).
Procedures
Procedures refer to the instructions and rules that help to design the database and to use the DBMS. The users that operate and manage the DBMS require documented procedures on hot use or run the database management system. These may include.
  1. Procedure to install the new DBMS.
  2. To log on to the DBMS.
  3. To use the DBMS or application program.
  4. To make backup copies of database.
  5. To change the structure of database.
  6. To generate the reports of data retrieved from database.
Database Access Language
    The database access language is used to access the data to and from the database. The users use the database access language to enter new data, change the existing data in database and to retrieve required data from databases. The user write a set of appropriate commands in a database access language and submits these to the DBMS. The DBMS translates the user commands and sends it to a specific part of the DBMS called the Database Jet Engine. The database engine generates a set of results according to the commands submitted by user, converts these into a user readable form called an Inquiry Report and then displays them on the screen. The administrators may also use the database access language to create and maintain the databases.
    The most popular database access language is SQL (Structured Query Language). Relational databases are required to have a database query language.
    Users
    The users are the people who manage the databases and perform different operations on the databases in the database system.There are three kinds of people who play different roles in database system
    1. Application Programmers
    2. Database Administrators
    3. End-Users
    Application Programmers
    The people who write application programs in programming languages (such as Visual Basic, Java, or C++) to interact with databases are called Application Programmer.
    Database Administrators 
    A person who is responsible for managing the overall database management system is called database administrator or simply DBA.
    End-Users
    The end-users are the people who interact with database management system to perform different operations on database such as retrieving, updating, inserting, deleting data etc.

    Copy and Paste from :
    http://computer-dbms.blogspot.com/2011_09_01_archive.html
    for studies :)

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