Data Base Management System

A database system or data base management system refers to an organization of components that define and regulate the collection, storage, management and use of data within a database environment. It consists of four main parts:

• Data
• Hardware
• Software
• Users (People)

Data: From the user's point of view, the most important component of database system is perhaps the data. The totality of data in the system is all stored in a single database. These data in a database are both integrated and shared in a system. Data integration means that the database can be thought of as a function of several otherwise distinct files, with at least partly eliminated redundancy among the files. Whereas in data sharing, individual pieces of data in the database can be shared among different users and each of those users can have access to the same piece of data, possibly for different purposes. Different users can effectively even access the same piece of data concurrently (at the same time). Such concurrent access of data by different users is possibly because of the fact that the database is integrated.

Depending on the size and requirement of an organization or enterprise, database systems are available on machines ranging from the small personal computers to the large mainframe computers. The requirement could be a single-user system (in which at most one user can access the database at a given time) or multi-user system (in which many users can access the database at the same time).

Hardware: All the physical devices of a computer are termed as hardware. The computer can range from a personal computer (microcomputer), to a minicomputer, to a single mainframe, to a network of computers, depending upon the organization’s requirement and the size of the database. From the point of view of the database system the hardware can be divided into two components: The processor and associated main memory to support the execution of database system (data base management system) software and The secondary (or external) storage devices (for example, hard disk, magnetic disks, compact disks and so on) that are used to hold the stored data, together with the associated peripherals (for example, input/output devices, device controllers, input/output channels and so on).

A database system requires a minimum amount of main memory and disk space to run. With a large number of users, a very large amount of main memory and disk space is required to maintain and control the huge quantity of data stored in a database. In addition, high-speed computers, networks and peripherals are necessary to execute the large number of data access required to retrieve information in an acceptable amount of time. The advancement in computer hardware technology and development of powerful and less expensive computers have resulted into increased database technology development and its application.

Software: Software is the basic interface (or layer) between the physical database and the users. It is most commonly known as database management system (data base management system). It comprises the application programs together with the operating system software. AH requests from the users to access the database are handled by data base management system. Data base management system provides various facilities, such as adding and deleting files, retrieving and updating data in the files and so on. Application software is generally written by company employees to solve a specific common problem.

Questionnaire:

• Explain about the data base management system?