Function

ALTER DEFAULT PRIVILEGES allows you to set the permissions that will be used for objects to be created. It does not affect permissions assigned to existing objects.

A user can modify only the default permissions of objects created by the user or the role to which the user belongs. These permissions can be set globally (all objects created in the database) or for objects in a specified schema.

To view information about the default permissions of database users, query the system catalog .

Precautions

Only the permissions for tables (including views), sequences, functions, and types (including domains) can be altered.

Syntax

ALTER DEFAULT PRIVILEGES
    [ FOR { ROLE | USER } target_role [, ...] ]
    [ IN SCHEMA schema_name [, ...] ]
    abbreviated_grant_or_revoke;

abbreviated_grant_or_revoke grants or revokes permissions on certain objects.

grant_on_tables_clause
  | grant_on_functions_clause
  | grant_on_types_clause
  | grant_on_sequences_clause
  | revoke_on_tables_clause
  | revoke_on_functions_clause
  | revoke_on_types_clause
  | revoke_on_sequences_clause

grant_on_tables_clause grants permissions on tables.

GRANT { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | TRIGGER | ANALYZE | ANALYSE | VACUUM | ALTER | DROP } 
    [, ...] | ALL [ PRIVILEGES ] }
    ON TABLES 
    TO { [ GROUP ] role_name | PUBLIC } [, ...]
    [ WITH GRANT OPTION ]

grant_on_functions_clause grants permissions on functions.

GRANT { EXECUTE | ALL [ PRIVILEGES ] }
    ON FUNCTIONS 
    TO { [ GROUP ] role_name | PUBLIC } [, ...]
    [ WITH GRANT OPTION ]

grant_on_types_clause grants permissions on types.

GRANT { USAGE | ALL [ PRIVILEGES ] }
    ON TYPES 
    TO { [ GROUP ] role_name | PUBLIC } [, ...]
    [ WITH GRANT OPTION ]

grant_on_sequences_clause grants permissions on sequences.

GRANT { { USAGE | SELECT | UPDATE }
    [, ...] | ALL [ PRIVILEGES ] }
    ON SEQUENCES 
    TO { [ GROUP ] role_name | PUBLIC } [, ...]
    [ WITH GRANT OPTION ]

revoke_on_tables_clause revokes permissions on tables.

REVOKE [ GRANT OPTION FOR ]
    { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | TRIGGER | ANALYZE | ANALYSE | VACUUM | ALTER | DROP } 
    [, ...] | ALL [ PRIVILEGES ] }
    ON TABLES 
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT | CASCADE CONSTRAINTS ]

revoke_on_functions_clause revokes permissions on functions.

REVOKE [ GRANT OPTION FOR ]
    { EXECUTE | ALL [ PRIVILEGES ] }
    ON FUNCTIONS 
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT | CASCADE CONSTRAINTS ]

revoke_on_types_clause revokes permissions on types.

REVOKE [ GRANT OPTION FOR ]
    { USAGE | ALL [ PRIVILEGES ] }
    ON TYPES 
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT | CASCADE CONSTRAINTS ]

revoke_on_sequences_clause revokes permissions on sequences.

REVOKE [ GRANT OPTION FOR ]
    { { USAGE | SELECT | UPDATE }
    [, ...] | ALL [ PRIVILEGES ] }
    ON SEQUENCES 
    FROM { [ GROUP ] role_name | PUBLIC } [, ...]
    [ CASCADE | RESTRICT | CASCADE CONSTRAINTS ]

Parameter Description

target_role
Specifies the name of an existing role. If FOR ROLE/USER is omitted, the current role or user is assumed.

target_role must have the CREATE permissions for schema_name. You can use the has_schema_privilege function to check whether a role or user has the CREATE permission on a schema.
1
SELECT a.rolname, n.nspname FROM pg_authid as a, pg_namespace as n WHERE has_schema_privilege(a.oid, n.oid, 'CREATE');
Value range: An existing role name.
schema_name
Indicates the name of an existing schema. If a schema name is specified, the default permissions of all objects created in the schema will be modified. If IN SCHEMA is omitted, global permissions will be modified.

Value range: An existing schema name.
role_name
Specifies the name of an existing role whose permissions are to be granted or revoked.

Value range: An existing role name.

To drop a role for which the default permissions have been assigned, to reverse the changes in its default permissions or use DROP OWNED BY to get rid of the default privileges entry for the role.

Examples

Run the following statements to create two users:

CREATE USER jack PASSWORD '{Password}';

Creating mode:

CREATE SCHEMA tpcds;

Grant the SELECT permission on all the tables (and views) in tpcds to every user.

ALTER DEFAULT PRIVILEGES IN SCHEMA tpcds GRANT SELECT ON TABLES TO PUBLIC;

Grant the INSERT permission on all the tables in tpcds to the user jack.

ALTER DEFAULT PRIVILEGES IN SCHEMA tpcds GRANT INSERT ON TABLES TO jack;

Revoke the preceding permissions.

ALTER DEFAULT PRIVILEGES IN SCHEMA tpcds REVOKE SELECT ON TABLES FROM PUBLIC; 
ALTER DEFAULT PRIVILEGES IN SCHEMA tpcds REVOKE INSERT ON TABLES FROM jack;

Assume that there are two users test1 and test2. If you require that user test2 can query tables created by user test1, execute the following statements.

Create users test1 and test2:

CREATE USER test1 PASSWORD '{Password}';
CREATE USER test2 PASSWORD '{Password}';

Grant user test2 the schema permission of user test1.

GRANT usage, create ON SCHEMA test1 TO test2;

Grant user test2 the table query permission of user test1.

ALTER DEFAULT PRIVILEGES FOR USER test1 IN SCHEMA test1 GRANT SELECT ON tables TO test2;

Create a table as user test1.

SET ROLE test1 password '{Password}';
CREATE TABLE test3( a int, b int);

Run the following statement as user test2.

SET ROLE test2 password '{Password}';
SELECT * FROM test1.test3;

Helpful Links

GRANT, REVOKE