Functions of DBMS:
A primary goal of a DBMS is to provide a way to store and
retrieve database information in such a way that it should be both convenient
and efficient.
1.
Data Definition:
The data definition tells us that the DBMS must be able to
accept data definitions in source form and convert them to appropriate object
form. This means, the DBMS must include DDL processor or DDL compiler
components for each of the various data definition languages (DDLs).
2.
Data Manipulation:
The DBMS must be able to handle requests to add new data to
the database, retrieve, update, or delete existing data in the database. This
means, the DBMS must include DML processor DML compiler components for each of
the various data manipulation languages (DMLs).
3.
Optimization and Execution:
DML requests, whether planned or unplanned, must be processed
by the optimizer component whose purpose is to determine an efficient way of
implementing the request. These optimized requests are then executed under the
control of runtime manager.
4.
Data Security and Integrity:
A DBMS must have a mechanism to monitor user requests and be
able to reject any attempts that violate the security constraints defined by the
DBA. These tasks can be carried out at compile time or runtime or sometimes a combination
of both.
5.
Data Recovery and Concurrency:
To implement this functionality, a DBMS or some other
software component called Transaction Manager or Transaction Processing Monitor
must enforce certain recovery and concurrency controls.
6.
Data Dictionary:
A DBMS must provide a data dictionary function. A data dictionary is a database which
contains ‘data about data’ called as metadata
or descriptor. Instead of raw data,
it contains definition of other objects in the system.
7.
Performance:
DBMS should perform all of the tasks mentioned above as
efficiently as possible. Further, the system should process data and generate
the results in an efficient way.
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