SQL Commands | DDL, DML, TCL, DCL, DQL

SQL Commands:

SQL Command

 

SQL commands are guidelines, coded into SQL proclamations, which are utilized to speak with the database to perform explicit undertakings, work, capacities and inquiries with information.
SQL commands can be utilized for looking through the database as well as to perform different capacities like, for instance, you can make tables, add information to tables, or alter information, drop the table, set consents for clients. SQL directions are assembled into four noteworthy classifications relying upon their usefulness:

Information Definition Language (DDL) -

These SQL commands are used for making, altering, and dropping the structure of database objects. The commands are CREATE, ALTER, DROP, RENAME, and TRUNCATE.

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Information Manipulation Language (DML) -

These SQL commands are used for putting away, recovering, changing, and erasing information.
These Data Manipulation Language commands are: INSERT, UPDATE, and DELETE.

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Exchange Control Language (TCL) -

These SQL commands are used for overseeing changes influencing the information. These commands are COMMIT, ROLLBACK, and SAVEPOINT.

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Information Control Language (DCL) -

These SQL commands are used for giving security to database objects. These commands are GRANT and REVOKE.

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Data Query Language (DQL) -

This SQL command is used for retrieve value from database. This command is SELECT.

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Recommended :

Data Definition Language :
	Create
	Drop
	Alter
	Truncate
Data Manipulation Language :
	Insert
	Update
	Delete
Data Control Language :
	Grant
	Revoke
Transaction Control Language :
	Commit
	Rollback
	Savepoint
Data Query Language:
	Select

REVOKE | Revoke Commands In SQL | DCL Command

REVOKE Command

Revoke command used to removes user access rights or privileges to the database objects.

Syntax :

REVOKE privilege_list ON object_name
FROM {user_name | PUBLIC | role_name};
Revoke command has four types of parameters:

1) privilege_list - This parameter specifies the types of privilege.
2) object_name - This parameter specifies the name of the database object like table, view etc.
3) user_name - This parameter specifies the name of the user.
4) role_name - This parameter specifies set of privileges grouped together.

Keyword

PUBLIC - Used to revoke rights to all user.

Example :

REVOKE SELECT ON Customer01 FROM user1;

* * * * * * * * * * * * * * * * * *

In Easy Language :

Revoke command used to remove user access privileges.

GRANT | Grant Command In SQL | DCL Command

GRANT Command

Grant command used to provide access or privileges on the database objects to the users.

Syntax :

GRANT privilege_list ON object_name
TO {user_name | PUBLIC | role_name}
[with GRANT option];


Grant command has five types of parameter :

1) privilege_list - This parameter specifies the access right or privilege granted to
the user.

2) object_name - This parameter specifies the name of the database object like table, view
etc.

3) user_name - This parameter specifies the name of the user to whom an access right is
being granted.

4) with GRANT option - It allows users to grant access rights to other
users.

5) role_name - This parameter specifies set of privileges grouped together.

Keyword

PUBLIC - Used to grant rights to all the users.

Example :
 
GRANT SELECT ON Customer01 TO user1 ;

* * * * * * * * * * * * * * * * *

In Easy Language :

Grant command used to access privileges.

DCL | Data Control Language

Data Control Language

In SQL, there are following two types of DCL commands. As under

• GRANT
• REVOKE

DCL commands are used to control privileges in Database. To perform any operation in the database, link., creating tables, sequences or views, a user needs privileges etc.
Here two types of privileges. As below :

1) System :  This privileges includes permissions for creating session, table etc and all types of other system privileges.

2) Object : This privileges includes permission for any command or query to perform any database tables.

GRANT Command

Grant command used to provide access or privileges on the database objects to the users.

Syntax :

GRANT privilege_list
ON object_name
TO {user_name | PUBLIC | role_name}
[WITH GRANT OPTION];
Example :

GRANT ALL ON Custome01
TO User01;
[WITH GRANT OPTION]

REVOKE Command 

Revoke command used to cancel previously granted or denied permissions.

Syntax :

REVOKE privilege_list
ON object_name
FROM {user_name | PUBLIC | role_name}

Example :

REVOKE UPDATE
ON Customer01
FROM User05;

* * * * * * * * * * * * * * * * *

In Easy Language

Grant - This command used to provide privileges to the user.
Revoke - This command used to take back or cancel privileges from user.

Recommended :

GRANT Command
REVOKE Command