RDBMS : Functional Components of a Database Management System

A database management system comparises many modules each dealing with a specific responsibility of the overall system. The functional components of a database management system are :

a. Database Manager
The database manager is the central software component of a DBMS. It is responsible for converting users queries to appropriate system calls. It maintains the consistency and integrity of the database and enforces data security. It also synchronizes the simultaneous operations performed by concurrent users. Apart from these, it also handles backup and recovery operations.

b. File Manager
The file manager services all requests for data. It identifies the block containing the requested record. The block is then requested from the disk manager. The file manager selects the requested record from the block and transmits it to the database manager. The file manager is also responsible for managing storage space and structures.

c. Disk Manager
The disk manager performs all the physical input and output. It interacts with the file manager and does read or write on the storage device as requested by the file manager. It views all data as row data. The operations performed by the disk manager are :
 Retrieves blocks of data
 Replaces blocks of data
 Removes blocks of data