SQL > Data Control Language (DCL)

Introduction

Data Control Language (DCL) is a subset of SQL that is used to control access to data in a database. It helps in defining user permissions and restricting unauthorized access.

Key DCL Commands:

• GRANT - Provides specific privileges to users.
• REVOKE - Removes privileges from users.

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GRANT

Purpose:

The GRANT command is used to give specific privileges to a user in the database.

Syntax:

GRANT privilege_name ON object_name TO user_name;

Examples:

Grant SELECT permission on a table:

GRANT SELECT ON Employees TO 'john'@'localhost';

Grant multiple privileges:

GRANT SELECT, INSERT, UPDATE ON Employees TO 'admin'@'localhost';

Grant all privileges on a database:

GRANT ALL PRIVILEGES ON CompanyDB.* TO 'manager'@'localhost';

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REVOKE

Purpose:

The REVOKE command is used to remove previously granted privileges from a user.

Syntax:

REVOKE privilege_name ON object_name FROM user_name;

Examples:

Revoke SELECT permission from a user:

REVOKE SELECT ON Employees FROM 'john'@'localhost';

Revoke multiple privileges:

REVOKE SELECT, INSERT ON Employees FROM 'admin'@'localhost';

Revoke all privileges from a user:

REVOKE ALL PRIVILEGES ON CompanyDB.* FROM 'manager'@'localhost';

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Summary

Command	Description
GRANT	Provides specific privileges to users.
REVOKE	Removes privileges from users.

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