REVOKE

Purpose

Use the REVOKE statement to:

• Revoke system privileges from users and roles

• Revoke roles from users and roles

• Revoke object privileges for a particular object from users and roles

  
  

  See Also: GRANT for information on granting system privileges and roles Table 18-3 for a summary of the object privileges for each type of object

  
  

Prerequisites

To revoke a system privilege, you must have been granted the privilege with the ADMIN OPTION.

To revoke a role, you must have been granted the role with the ADMIN OPTION. You can revoke any role if you have the GRANT ANY ROLE system privilege.

To revoke an object privilege, you must previously have granted the object privilege to the user and role or you must have the GRANT ANY OBJECT PRIVILEGE system privilege. In the latter case, you can revoke any object privilege that was granted by the object owner or on behalf of the owner—that is, by a user with the GRANT ANY OBJECT PRIVILEGE. However, you cannot revoke an object privilege that was granted by way of a WITH GRANT OPTION grant.

The REVOKE statement can revoke only privileges and roles that were previously granted directly with a GRANT statement. You cannot use this statement to revoke:

• Privileges or roles not granted to the revokee

• Roles or object privileges granted through the operating system

• Privileges or roles granted to the revokee through roles

Syntax

revoke::=

Description of the illustration revoke.gif

(revoke_system_privileges::=, revoke_object_privileges::=)

revoke_system_privileges::=

Description of the illustration revoke_system_privileges.gif

(grantee_clause::=)

revoke_object_privileges::=

Description of the illustration revoke_object_privileges.gif

(on_object_clause::=, grantee_clause::=)

grantee_clause::=

Description of the illustration grantee_clause.gif


on_object_clause::=

Description of the illustration on_object_clause.gif

Semantics

revoke_system_privileges

Use these clauses to revoke system privileges.

system_privilege

Specify the system privilege to be revoked. Please refer to Table 18-1 for a list of the system privileges.

If you revoke a system privilege from a user, then the database removes the privilege from the user's privilege domain. Effective immediately, the user cannot exercise the privilege.

If you revoke a system privilege from a role, then the database removes the privilege from the privilege domain of the role. Effective immediately, users with the role enabled cannot exercise the privilege. Also, other users who have been granted the role and subsequently enable the role cannot exercise the privilege.

If you revoke a system privilege from PUBLIC, then the database removes the privilege from the privilege domain of each user who has been granted the privilege through PUBLIC. Effective immediately, such users can no longer exercise the privilege. However, the privilege is not revoked from users who have been granted the privilege directly or through roles.

Oracle Database provides a shortcut for specifying all system privileges at once: Specify ALL PRIVILEGES to revoke all the system privileges listed in Table 18-1.

Restriction on Revoking System Privileges

A system privilege cannot appear more than once in the list of privileges to be revoked.

role

Specify the role to be revoked.

If you revoke a role from a user, then the database makes the role unavailable to the user. If the role is currently enabled for the user, the user can continue to exercise the privileges in the role's privilege domain as long as it remains enabled. However, the user cannot subsequently enable the role.

If you revoke a role from another role, then the database removes the privilege domain of the revoked role from the privilege domain of the revokee role. Users who have been granted and have enabled the revokee role can continue to exercise the privileges in the privilege domain of the revoked role as long as the revokee role remains enabled. However, other users who have been granted the revokee role and subsequently enable it cannot exercise the privileges in the privilege domain of the revoked role.

If you revoke a role from PUBLIC, then the database makes the role unavailable to all users who have been granted the role through PUBLIC. Any user who has enabled the role can continue to exercise the privileges in its privilege domain as long as it remains enabled. However, users cannot subsequently enable the role. The role is not revoked from users who have been granted the role directly or through other roles.

Restriction on Revoking System Roles

A system role cannot appear more than once in the list of roles to be revoked. Please refer to Table 18-2 for a list of the roles predefined by Oracle Database.

grantee_clause

FROM grantee_clause identifies users or roles from which the system privilege, role, or object privilege is to be revoked.

PUBLIC

Specify PUBLIC to revoke the privileges or roles from all users.

revoke_object_privileges

Use these clauses to revoke object privileges.

object_privilege

Specify the object privilege to be revoked. You can substitute any of the object privileges listed on Table 18-2.

If you revoke an object privilege from a user, then the database removes the privilege from the user's privilege domain. Effective immediately, the user cannot exercise the privilege.

• If that user has granted that privilege to other users or roles, then the database also revokes the privilege from those other users or roles.

• If that user's schema contains a procedure, function, or package that contains SQL statements that exercise the privilege, then the procedure, function, or package can no longer be executed.

• If that user's schema contains a view on that object, then the database invalidates the view.

• If you revoke the REFERENCES object privilege from a user who has exercised the privilege to define referential integrity constraints, then you must specify the CASCADE CONSTRAINTS clause.

If you revoke an object privilege from a role, then the database removes the privilege from the privilege domain of the role. Effective immediately, users with the role enabled cannot exercise the privilege. Other users who have been granted the role cannot exercise the privilege after enabling the role.

If you revoke an object privilege from PUBLIC, then the database removes the privilege from the privilege domain of each user who has been granted the privilege through PUBLIC. Effective immediately, all such users are restricted from exercising the privilege. However, the privilege is not revoked from users who have been granted the privilege directly or through roles.

ALL [PRIVILEGES]

Specify ALL to revoke all object privileges that you have granted to the revokee. (The keyword PRIVILEGES is provided for semantic clarity and is optional.)

If no privileges have been granted on the object, then the database takes no action and does not return an error.

Restriction on Revoking Object Privileges

A privilege cannot appear more than once in the list of privileges to be revoked. A user, a role, or PUBLIC cannot appear more than once in the FROM clause.

CASCADE CONSTRAINTS

This clause is relevant only if you revoke the REFERENCES privilege or ALL [PRIVILEGES]. It drops any referential integrity constraints that the revokee has defined using the REFERENCES privilege, which might have been granted either explicitly or implicitly through a grant of ALL [PRIVILEGES].

FORCE

Specify FORCE to revoke the EXECUTE object privilege on user-defined type objects with table or type dependencies. You must use FORCE to revoke the EXECUTE object privilege on user-defined type objects with table dependencies.

If you specify FORCE, then all privileges are revoked, all dependent objects are marked INVALID, data in dependent tables becomes inaccessible, and all dependent function-based indexes are marked UNUSABLE. Regranting the necessary type privilege will revalidate the table.

on_object_clause

The on_object_clause identifies the objects on which privileges are to be revoked.

object

Specify the object on which the object privileges are to be revoked. This object can be:

• A table, view, sequence, procedure, stored function, or package, materialized view

• A synonym for a table, view, sequence, procedure, stored function, package, materialized view, or user-defined type

• A library, indextype, or user-defined operator

If you do not qualify object with schema, then the database assumes the object is in your own schema.

If you revoke the SELECT object privilege, with or without the GRANT OPTION, on the containing table or materialized view of a materialized view, then the database invalidates the materialized view.

If you revoke the SELECT object privilege, with or without the GRANT OPTION, on any of the master tables of a materialized view, then the database invalidates both the materialized view and its containing table or materialized view.

DIRECTORY directory_name

Specify the directory object on which privileges are to be revoked. You cannot qualify directory_name with schema. The object must be a directory.

JAVA SOURCE | RESOURCE

The JAVA clause lets you specify a Java source or resource schema object on which privileges are to be revoked.

Examples

Revoking a System Privilege from a User: Example

The following statement revokes the DROP ANY TABLE system privilege from the users hr and oe:

REVOKE DROP ANY TABLE 
    FROM hr, oe; 

The users hr and oe can no longer drop tables in schemas other than their own.

Revoking a Role from a User: Example

The following statement revokes the role dw_manager from the user sh:

REVOKE dw_manager 
    FROM sh; 

The user sh can no longer enable the dw_manager role.

Revoking a System Privilege from a Role: Example

The following statement revokes the CREATE TABLESPACE system privilege from the dw_manager role:

REVOKE CREATE TABLESPACE 
   FROM dw_manager; 

Enabling the dw_manager role no longer allows users to create tablespaces.

Revoking a Role from a Role: Example

To revoke the role dw_user from the role dw_manager, issue the following statement:

REVOKE dw_user
  FROM dw_manager; 

The dw_user role privileges are no longer granted to dw_manager.

Revoking an Object Privilege from a User: Example

You can grant DELETE, INSERT, SELECT, and UPDATE privileges on the table orders to the user hr with the following statement:

GRANT ALL 
   ON orders TO hr; 

To revoke the DELETE privilege on orders from hr, issue the following statement:

REVOKE DELETE 
   ON orders FROM hr; 

Revoking All Object Privileges from a User: Example

To revoke the remaining privileges on orders that you granted to hr, issue the following statement:

REVOKE ALL 
   ON orders FROM hr; 

Revoking Object Privileges from PUBLIC: Example

You can grant SELECT and UPDATE privileges on the view emp_details_view to all users by granting the privileges to the role PUBLIC:

GRANT SELECT, UPDATE 
    ON emp_details_view TO public; 

The following statement revokes UPDATE privilege on emp_details_view from all users:

REVOKE UPDATE 
    ON emp_details_view FROM public;

Users can no longer update the emp_details_view view, although users can still query it. However, if you have also granted the UPDATE privilege on emp_details_view to any users, either directly or through roles, then these users retain the privilege.

Revoking an Object Privilege on a Sequence from a User: Example

You can grant the user oe the SELECT privilege on the departments_seq sequence in the schema hr with the following statement:

GRANT SELECT 
    ON hr.departments_seq TO oe; 

To revoke the SELECT privilege on departments_seq from oe, issue the following statement:

REVOKE SELECT 
    ON hr.departments_seq FROM oe; 

However, if the user hr has also granted SELECT privilege on departments to sh, then sh can still use departments by virtue of hr's grant.

Revoking an Object Privilege with CASCADE CONSTRAINTS: Example

You can grant to oe the privileges REFERENCES and UPDATE on the employees table in the schema hr with the following statement:

GRANT REFERENCES, UPDATE 
    ON hr.employees TO oe; 

The user oe can exercise the REFERENCES privilege to define a constraint in his or her own dependent table that refers to the employees table in the schema hr:

CREATE TABLE dependent 
(dependno   NUMBER, 
 dependname VARCHAR2(10), 
 employee   NUMBER                   
    CONSTRAINT in_emp REFERENCES hr.employees(employee_id) ); 

You can revoke the REFERENCES privilege on hr.employees from oe by issuing the following statement that contains the CASCADE CONSTRAINTS clause:

REVOKE REFERENCES 
    ON hr.employees 
    FROM oe 
    CASCADE CONSTRAINTS; 

Revoking oe's REFERENCES privilege on hr.employees causes Oracle Database to drop the in_emp constraint, because oe required the privilege to define the constraint.

However, if oe has also been granted the REFERENCES privilege on hr.employees by a user other than you, then the database does not drop the constraint. oe still has the privilege necessary for the constraint by virtue of the other user's grant.

Revoking an Object Privilege on a Directory from a User: Example

You can revoke the READ object privilege on directory bfile_dir from hr by issuing the following statement:

REVOKE READ ON DIRECTORY bfile_dir FROM hr;

Revoke Operations that Use GRANT ANY OBJECT PRIVILEGE: Example

Suppose that the database administrator has granted GRANT ANY OBJECT PRIVILEGE to user sh. Now suppose that user hr grants the update privilege on the employees table to oe:

CONNECT hr/hr
GRANT UPDATE ON employees TO oe WITH GRANT OPTION;

This grant gives user oe the right to pass the object privilege along to another user:

CONNECT oe/oe
GRANT UPDATE ON hr.employees TO pm;

User sh, who has the GRANT ANY OBJECT PRIVILEGE, can now act on behalf of user hr and revoke the update privilege from user oe, because oe was granted the privilege by hr:

CONNECT sh/sh
REVOKE UPDATE ON hr.employees FROM oe;

User sh cannot revoke the update privilege from user pm explicitly, because pm received the grant neither from the object owner (hr), nor from sh, nor from another user with GRANT ANY OBJECT PRIVILEGE, but from user oe. However, the preceding statement cascades, removing all privileges that depend on the one revoked. Therefore the object privilege is implicitly revoked from pm as well.