The database management system (DBMS) software is divided into several components. Each component will perform a specific operation. Some of the functions of the DBMS are supported by operating systems.
The DBMS accepts the SQL commands that are generated from a variety of user interfaces, which produces a query evaluation plan, executes these plans against the database, and returns the answers.
Let’s have a look on the major software components of DBMS with pictorial representation −
The components of the DBMS are as follows −
DBA − The Data Base Administrator (DBA) responsibility is to create the DBMS structure and have the ability to control the structure.
Application Programs − It is used to create the records, change and update the records. It is mainly useful in designing the interface.
DML processor − Data Manipulation language, it is helpful to update data, manipulate data based on user request, checks according to syntax of SQL.
DDL Processor − Data Definition language checks the structure of the database. It checks the improper statements and the syntax of statements according to the SQL.
Data Dictionary − Store all the queries. Queries are checked according to the SQL configuration, if the queries are valid ok. Otherwise, it generates errors.
Integrity Checker − Here data is stored which is designed by Database administrator. Check the primary or unique key.
Authenticate control − Authenticate control checks whether a user is valid or not.
Command Processor − It processes the query ->SQL. For example, SQL ->Oracle -> optimize -> generate file.
Query optimizer − It updates the query, Reduces response time at end.
Transaction manager − Transaction manager, manage changes in query.
Scheduler − Send number of requests at a time, A queue is formed according to time.
Buffer manager − Buffer manager performs storage management operation.
Recovery manager − Recovery manager recovers the data from main memory and manages the log files or recovery files.
Query processor − Query processor processes the query coming from the user side. Its responsibility is to manage DML and DDL commands.
Select emp name, address from emp; Select is a DML command.
Both processors work at the same time.
Syntax table is created or not.
Run select query which is retrieved from hard disk.
Run-time database performs the operations mentioned below −
Data manager performs the physical level working and monitors how much space to be allocated to the database (DB).