Components of Database Management System
The components of a Database Management System include all the necessary devices, software, procedures, users, etc. to make a Database Management System fully functional.
Generally, components of DBMS are categorized into six major components i.e.
i. Software
Software is a set of programs that are used to control and manage the overall database. It includes the following kinds of software:
a. DBMS Software: A DBMS Software itself, is the most important software component in the overall database. A DBMS allows the database users to store, retrieve, query, update and manage data in the database. Some of the examples of DBMS Software are Oracle, MsAceess, PostgreSQL, FoxPro, dBase, etc.
b. Operating System: An operating system provides the interface to operate the DBMS in a computer. Without an operating system, it is impossible to run the DBMS on the computer. Also, the operating system provides the ability to input data to DBMS using input devices like keyboard, display the records using the output device like monitor, printer, plotter, etc., store the data in storage medium like hard drive, Pen drive, etc. An operating system including the network software is also used to share the data of the database among multiple users.
c. Application programs: Application programs are used to access data in the DBMS. They are developed in programming languages such as C++, Visual Basic, etc. Each program contains the statements that request the DBMS to operate on the database. The operations may include retrieving, updating, deleting data, etc. The application program may be conventional or online workstations or terminals.
ii. Hardware
Hardware is another most important component of the DBMS. The hardware consists of a set of physical electronic devices such as computers, servers, I/O devices, storage devices, etc. The hardware devices provide the interface between the computers and real-world systems. It is also impossible to implement the DBMS without the hardware devices. Hardware device like the keyboard is used to input the data in the database, mouse to click the different operations in the GUI, storage device to store the database, display unit to show the records to users, a network to share the data to multiple users at a time. In a network, a powerful computer with high data processing speed and a storage device with large storage capacity is required as a database server.
iii. Data
Data is the most important component of the DBMS. Without the data, a database cannot be imagined. Sometimes the cost of data could be greater than the DBMS that operate those data. Here the main purpose of the DBMS is to process the data in the database. In DBMS data are defined, constructed and then data is stored, updated, and retrieved to and from the databases. A database contains both the actual (or operational) data and the metadata (data about data or description about data).
iv. Procedures
Procedures refer to the instructions and the rules that help to design the database and to use the database. The users that operate and manage the DB<S require documented procedures on how to use or run the database management system. They may include the following procedures like
- Procedure to install the new DBMS
- To log on to the DBMS
- To use the DBMS or application program
- To make backup copies of the database
- To change the structure of the database
- To generate the reports of data retrieved from the database.
v. Database Access Language
Database access language is a simple language designed to write commands to access, insert, update and delete data stored in any database. It is used to access data to and from the database, to enter new data, update existing data or retrieve required data from databases. The user writes the set of appropriate commands in a database access language, submits these to the DBMS, which then processes the data and generates and displays a set of results into a user-readable form. The most popular data access language is SQL (Structured Query Language).
vi. Users
Users are those people who manage the database and perform different operations on the database system. The users as categorized based on the role as follows:
a) Database Administrators
A database administrator is a person who has central control over the system. A database administrator takes care of the security, its ability, managing the licenses keys, managing user accounts and access, etc.
The functions of a database administrator include:
· Schema definition: The DBA creates the original database schema by executing a set of data definition statements in the DDL
· Schema and physical organization modification: The DBA carries out the changes to the schema and physical organization to reflect the changing needs of the organization, or to alter physical organization to improve performance.
· Granting of authorization for data access: By grating different types of authorization, the DBA can regulate different users accessing different parts of the database
· Routine maintenance: Examples of database administrator’s routine maintenance activities are:
o Periodic backup, either onto drives or onto remote servers, to prevent loss of data in a case in case of disasters.
o Ensuring that enough free disk space is available for normal operations and upgrading disk space as required
o Monitoring jobs running on the database and ensuring that performance is not degraded by very expensive tasks submitted by some users.
b) Application Programmer or Software Developer
This user group is involved in developing and designing the parts of DBMS. These users write application programs in programming languages such as Visual Basic, Java, or C+ to interact with the databases.
c) End Users
The end-users are the people who interact with the database management system to perform different operations on a database such as retrieving, updating, inserting deleting data, etc. The user may be a naïve user (who interact with the system by invoking one of the application programs that have been written previously) or a sophisticated user (they interact through database query language)