What does revoke mean in sql

The REVOKE command in SQL is used to revoke a user or role's access or operation permissions on database objects, thereby enhancing database security and correcting incorrectly granted permissions. The syntax is REVOKE [GRANT OPTION FOR] permission ON object FROM user_or_role. Specific usage includes: revoking the user's SELECT permission on the table, revoking all role permissions on the view, revoking the user's GRANT option, etc. Only users or roles with higher permissions can execute the REVOKE command, and the permissions will expire immediately after being revoked.

REVOKE in SQL

REVOKE represents the command to revoke permissions in SQL and is used to remove permissions from database users or Revoke permissions from a role to access or operate on database objects such as tables, views, or stored procedures.

Function

The REVOKE command is mainly used to:

• Revoke the permission of a user or role to access database objects.
• Improve database security through stricter permission control.
• Correction issues caused by incorrect granting.

Syntax

The syntax of the REVOKE command is as follows:

<code>REVOKE [GRANT OPTION FOR] permission ON object FROM user_or_role;</code>

Among them:

• [ GRANT OPTION FOR] permission: The permission to be revoked, such as SELECT, INSERT, or GRANT.
• object: The object to which permissions are to be revoked, such as a table or view.
• user_or_role: The user or role whose permissions are to be revoked.

Usage

The following are some examples of the REVOKE command:

• Revoke user john's SELECT permission on table my_table:

<code>REVOKE SELECT ON my_table FROM john;</code>

• Revoke all permissions of role admin_role on view my_view:

<code>REVOKE ALL ON my_view FROM admin_role;</code>

• Revoke user mary's GRANT option on table my_table:

<code>REVOKE GRANT OPTION FOR SELECT ON my_table FROM mary;</code>

Note

• Only users or roles with higher permissions than the permissions to be revoked can execute the REVOKE command.
• The REVOKE command will take effect immediately, and the revoked permissions will become invalid immediately.
• After revoking permissions, the user or role will no longer be able to access or operate the object.

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