The functions of Database Management System(DBMS) are as follows -
Data Definition - The DBMS must be able to accept data definitions in the source form and convert them to appropriate object form . In other words , the DBMS must include DDL processor or DDL compiler components for each of the various data definition languages (DDLs) .
Data Manipulation - The DBMS must be able to handle requests to retrieve , update, or delete existing data in the database or to add new data to the database . In other words , the DBMS must include a DML processor or DMLcompiler component to deal with the data manipulation language (DML) .
Optimization and Execution - DML requests , planned or unplanned , must be processed by the optimizer component whose purpose is to determine an efficient way of implementing the requests . The optimized requests are then executed under the control of the run-time manager .
Data Security and Integrity - The DBMS must monitor user requests and rejects any attempts
Data Recovery and Concurrency - The DBMS ,some other related software component , called the transaction manager or transaction processing monitor must enforce certain recovery and concurrency controls .
Data Dictionary - The DBMS must provide a data dictionary function . The data dictionary is a database which contains "data about data" (called meta data or descriptor) . In particular , all of the various schema's and mappings and all of the various security and integrity constraints will be stored in both source and object form , in the dictionary .
Performance - The DBMS should perform all of the tasks identified above as efficiently as possible .
For more of such hot topics read my other posts here :
Visit my new website