# REVOKE statement

Use the REVOKE statement to remove permissions from a specific user or role, or from all users, to perform actions on database objects. You can also use the REVOKE statement to revoke a role from a user, from PUBLIC, or from another role.

The following types of permissions can be revoked:

- Delete data from a specific table.
- Insert data into a specific table.
- Create a foreign key reference to the named table or to a subset of columns from a table.
- Select data from a table, view, or a subset of columns in a table.
- Create a trigger on a table.
- Update data in a table or in a subset of columns in a table.
- Run a specified routine (function or procedure).

The `derby.database.sqlAuthorization` property must be set to `true` before you can use the GRANT statement or the REVOKE statement. The `derby.database.sqlAuthorization` property enables SQL Authorization mode.

You can revoke privileges for an object if you are the owner of the object or the database owner.

The syntax that you use for the REVOKE statement depends on whether you are revoking privileges to a table or to a routine, or whether you are revoking a role.

For more information on using the REVOKE statement, see "Using SQL standard authorization" in the Derby Developer's Guide.

#### Syntax for tables

    REVOKE privilege-type ON [ TABLE ] { table-Name | view-Name } FROM grantees

Revoking a privilege without specifying a column list revokes the privilege for all of the columns in the table.

#### Syntax for routines

    REVOKE EXECUTE ON { FUNCTION | PROCEDURE } routine-designator FROM grantees  RESTRICT

You must use the RESTRICT clause on REVOKE statements for routines. The RESTRICT clause specifies that the EXECUTE privilege cannot be revoked if the specified routine is used in a view, trigger, or constraint, and the privilege is being revoked from the owner of the view, trigger, or constraint.

#### Syntax for roles

    REVOKE roleName [ {, roleName }* ] FROM grantees

Only the database owner can revoke a role.

#### privilege-types

      ALL PRIVILEGES |
      privilege-list

#### privilege-list

      table-privilege {, table-privilege }*

#### table-privilege

      DELETE |
      INSERT |
      REFERENCES [column list] |
      SELECT [column list] |
      TRIGGER |
      UPDATE [column list]

#### column list

      ( column-identifier {, column-identifier}* )

Use the ALL PRIVILEGES privilege type to revoke all of the permissions from the user or role for the specified table. You can also revoke one or more table privileges by specifying a privilege-list.

Use the DELETE privilege type to revoke permission to delete rows from the specified table.

Use the INSERT privilege type to revoke permission to insert rows into the specified table.

Use the REFERENCES privilege type to revoke permission to create a foreign key reference to the specified table. If a column list is specified with the REFERENCES privilege, the permission is revoked on only the foreign key reference to the specified columns.

Use the SELECT privilege type to revoke permission to perform SELECT statements on a table or view. If a column list is specified with the SELECT privilege, the permission is revoked on only those columns. If no column list is specified, then the privilege is valid on all of the columns in the table.

Use the TRIGGER privilege type to revoke permission to create a trigger on the specified table.

Use the UPDATE privilege type to revoke permission to use the UPDATE statement on the specified table. If a column list is specified, the permission is revoked only on the specified columns.

#### grantees

    { AuthorizationIdentifier | roleName | PUBLIC }
    [,{ AuthorizationIdentifier | roleName | PUBLIC } ] *

You can revoke the privileges from specific users or roles or from all users. Use the keyword PUBLIC to specify all users. The privileges revoked from PUBLIC and from individual users or roles are independent privileges. For example, a SELECT privilege on table `t` is granted to both PUBLIC and to the authorization ID `harry`. The SELECT privilege is later revoked from the authorization ID `harry`, but the authorization ID `harry` can access the table `t` through the PUBLIC privilege.

You can revoke a role from a role, from a user, or from PUBLIC.

Restriction: You cannot revoke the privileges of the owner of an object.

#### routine-designator

      {
       qualified-name [ signature ]
      }

#### Prepared statements and open result sets/cursors

Checking for privileges happens at statement execution time, so prepared statements are still usable after a revoke action. If sufficient privileges are still available for the session, prepared statements will be executed, and for queries, a result set will be returned.

Once a result set has been returned to the application (by executing a prepared statement or by direct execution), it will remain accessible even if privileges or roles are revoked in a way that would cause another execution of the same statement to fail.

#### Cascading object dependencies

For views, triggers, and constraints, if the privilege on which the object depends on is revoked, the object is automatically dropped. Derby does not try to determine if you have other privileges that can replace the privileges that are being revoked. For more information, see "SQL standard authorization" in the Derby Developer's Guide.

#### Limitations

The following limitations apply to the REVOKE statement:

Table-level privileges
  All of the table-level privilege types for a specified grantee and table ID are stored in one row in the SYSTABLEPERMS system table. For example, when `user2` is granted the SELECT and DELETE privileges on table `user1.t1`, a row is added to the SYSTABLEPERMS table. The GRANTEE field contains `user2` and the TABLEID contains `user1.t1`. The SELECTPRIV and DELETEPRIV fields are set to Y. The remaining privilege type fields are set to N.

  When a grantee creates an object that relies on one of the privilege types, the Derby engine tracks the dependency of the object on the specific row in the SYSTABLEPERMS table. For example, `user2` creates the view `v1` by using the statement `SELECT * FROM user1.t1`, the dependency manager tracks the dependency of view `v1` on the row in SYSTABLEPERMS for GRANTEE(`user2`), TABLEID(`user1.t1`). The dependency manager knows only that the view is dependent on a privilege type in that specific row, but does not track exactly which privilege type the view is dependent on.

  When a REVOKE statement for a table-level privilege is issued for a grantee and table ID, all of the objects that are dependent on the grantee and table ID are dropped. For example, if `user1` revokes the DELETE privilege on table `t1` from `user2`, the row in SYSTABLEPERMS for GRANTEE(`user2`), TABLEID(`user1.t1`) is modified by the REVOKE statement. The dependency manager sends a revoke invalidation message to the view `user2.v1` and the view is dropped even though the view is not dependent on the DELETE privilege for GRANTEE(`user2`), TABLEID(`user1.t1`).

Column-level privileges
  Only one type of privilege for a specified grantee and table ID are stored in one row in the SYSCOLPERMS system table. For example, when `user2` is granted the SELECT privilege on table `user1.t1` for columns c12 and c13, a row is added to the SYSCOLPERMS. The GRANTEE field contains `user2`, the TABLEID contains `user1.t1`, the TYPE field contains `S`, and the COLUMNS field contains `c12, c13`.

  When a grantee creates an object that relies on the privilege type and the subset of columns in a table ID, the Derby engine tracks the dependency of the object on the specific row in the SYSCOLPERMS table. For example, `user2` creates the view `v1` by using the statement `SELECT c11 FROM user1.t1`, the dependency manager tracks the dependency of view `v1` on the row in SYSCOLPERMS for GRANTEE(`user2`), TABLEID(`user1.t1`), TYPE(S). The dependency manager knows that the view is dependent on the SELECT privilege type, but does not track exactly which columns the view is dependent on.

  When a REVOKE statement for a column-level privilege is issued for a grantee, table ID, and type, all of the objects that are dependent on the grantee, table ID, and type are dropped. For example, if `user1` revokes the SELECT privilege on column `c12` on table `user1.t1` from `user2`, the row in SYSCOLPERMS for GRANTEE(`user2`), TABLEID(`user1.t1`), TYPE(S) is modified by the REVOKE statement. The dependency manager sends a revoke invalidation message to the view `user2.v1` and the view is dropped even though the view is not dependent on the column `c12` for GRANTEE(`user2`), TABLEID(`user1.t1`), TYPE(S).

Roles
  Derby tracks any dependencies on the definer's current role for views, constraints, and triggers. If privileges were obtainable only via the current role when the object in question was defined, that object depends on the current role. The object will be dropped if the role is revoked from the defining user or from PUBLIC, as the case may be. Also, if a contained role of the current role in such cases is revoked, dependent objects will be dropped. Note that dropping may be too pessimistic. This is because Derby does not currently make an attempt to recheck if the necessary privileges are still available in such cases.

#### Revoke examples

To revoke the SELECT privilege on table `t` from the authorization IDs `maria` and `harry`, use the following syntax:

    REVOKE SELECT ON TABLE t FROM maria,harry

To revoke the UPDATE and TRIGGER privileges on table `t` from the authorization IDs `anita` and `zhi`, use the following syntax:

    REVOKE UPDATE, TRIGGER ON TABLE t FROM anita,zhi

To revoke the SELECT privilege on table `s.v` from all users, use the following syntax:

    REVOKE SELECT ON TABLE s.v FROM PUBLIC

To revoke the UPDATE privilege on columns `c1` and `c2` of table `s.v` from all users, use the following syntax:

    REVOKE UPDATE (c1,c2) ON TABLE s.v FROM PUBLIC

To revoke the EXECUTE privilege on procedure `p` from the authorization ID `george`, use the following syntax:

    REVOKE EXECUTE ON PROCEDURE p FROM george RESTRICT

To revoke the role `purchases_reader_role` from the authorization IDs `george` and `maria`, use the following syntax:

    REVOKE purchases_reader_role FROM george,maria

To revoke the SELECT privilege on table `t` from the role `purchases_reader_role`, use the following syntax:

    REVOKE SELECT ON TABLE t FROM purchases_reader_role

Parent topic: Statements
Related concepts
Using SQL standard authorization
Related reference
GRANT statement
SYSCOLPERMS system table
SYSTABLEPERMS system table