Tuesday, 12 July 2011

Components of database management

Components of Database System
A database management system is a collection of interrelated data and a set of programs to access that data. The collection of data is called database, which contains information relevant to an enterprise. The main goal of DBMS is to provide a way to store and retrieve database information that is both convenient and efficient. Figure shows a database system.
Database Management System
Figure 1.1 Database system
The database system has four components: Data, Hardware, Software and Users.
(i) Data: Data refers to collection of related information, combined to be stored at a central place , which is the basic of any activity in the organization. It is that component, for whose management the DBMS works. It is the most important and essential component and is the core of any organization and its activity.
(ii) Hardware: The hardware components of the system consist of : 
    (a) The secondary storage devices such as magnetic tapes or disks which are used to hold large volumes of data, together with associated I/O devices, device controller, I/O channels and so on.
    (b) The hardware processor and associated main memory that are used to support the execution of the database system software.
(iii) Software: Between the physical database itself i.e. the data as physically stored and the users of the system, is a layer of software, known as Database  Manager or Database Management System (DBMS). All requests for access to database are handled by the DBMS.
(iv) Users: This component includes all types of users, who derive the benefit of getting their work done by the DBMS, so that they have the required data and information with them for decision making. Users are of four types:
 1. Application programmers or Ordinary users
 2. End users
 3. Database Administrator (DBA)
  4. System Ana.yst