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GRANT()				 SQL Commands			       GRANT()



NAME
       GRANT - define access privileges


SYNOPSIS
       GRANT { { SELECT | INSERT | UPDATE | DELETE | RULE | REFERENCES | TRIGGER }
	   [,...] | ALL [ PRIVILEGES ] }
	   ON [ TABLE ] tablename [, ...]
	   TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { { CREATE | TEMPORARY | TEMP } [,...] | ALL [ PRIVILEGES ] }
	   ON DATABASE dbname [, ...]
	   TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { EXECUTE | ALL [ PRIVILEGES ] }
	   ON FUNCTION funcname ( [ [ argmode ] [ argname ] argtype [, ...] ] ) [, ...]
	   TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { USAGE | ALL [ PRIVILEGES ] }
	   ON LANGUAGE langname [, ...]
	   TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { { CREATE | USAGE } [,...] | ALL [ PRIVILEGES ] }
	   ON SCHEMA schemaname [, ...]
	   TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { CREATE | ALL [ PRIVILEGES ] }
	   ON TABLESPACE tablespacename [, ...]
	   TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT role [, ...] TO username [, ...] [ WITH ADMIN OPTION ]


DESCRIPTION
       The GRANT command has two basic variants: one that grants privileges on
       a database object (table, view, sequence, database, function,  procedu-
       ral language, schema, or tablespace), and one that grants membership in
       a role. These variants are similar in many ways, but they are different
       enough to be described separately.

       As  of  PostgreSQL 8.1, the concepts of users and groups have been uni-
       fied into a single kind of entity called a role.	 It  is	 therefore  no
       longer necessary to use the keyword GROUP to identify whether a grantee
       is a user or a group. GROUP is still allowed in the command, but it  is
       a noise word.

   GRANT ON DATABASE OBJECTS
       This  variant  of  the  GRANT  command  gives  specific privileges on a
       database object to one or more roles. These  privileges	are  added  to
       those already granted, if any.

       The  key word PUBLIC indicates that the privileges are to be granted to
       all roles, including those that may be created  later.  PUBLIC  may  be
       thought	of  as	an  implicitly	defined group that always includes all
       roles.  Any particular role will have the  sum  of  privileges  granted
       directly to it, privileges granted to any role it is presently a member
       of, and privileges granted to PUBLIC.

       If WITH GRANT OPTION is specified, the recipient of the	privilege  may
       in  turn grant it to others. Without a grant option, the recipient can-
       not do that. Grant options cannot be granted to PUBLIC.

       There is no need to grant privileges to the owner of an object (usually
       the  user that created it), as the owner has all privileges by default.
       (The owner could, however, choose to revoke some of his own  privileges
       for  safety.)   The right to drop an object, or to alter its definition
       in any way is not described by a grantable privilege; it is inherent in
       the  owner,  and cannot be granted or revoked. The owner implicitly has
       all grant options for the object, too.

       Depending on the type of object, the  initial  default  privileges  may
       include	granting  some privileges to PUBLIC.  The default is no public
       access for tables, schemas, and tablespaces; TEMP table creation privi-
       lege  for  databases; EXECUTE privilege for functions; and USAGE privi-
       lege for languages.  The object owner may of course revoke these privi-
       leges.  (For maximum security, issue the REVOKE in the same transaction
       that creates the object; then there is no window in which another  user
       may use the object.)

       The possible privileges are:

       SELECT Allows  SELECT  [select(7)] from any column of the specified ta-
	      ble, view, or sequence.  Also allows the use of  COPY  [copy(7)]
	      TO.   This privilege is also needed to reference existing column
	      values  in  UPDATE  [update(7)]  or  DELETE  [delete(7)].	   For
	      sequences,  this	privilege  also	 allows the use of the currval
	      function.

       INSERT Allows INSERT [insert(7)] of a new row into the specified table.
	      Also allows COPY [copy(7)] FROM.

       UPDATE Allows  UPDATE [update(7)] of any column of the specified table.
	      (In practice, any nontrivial UPDATE command will require	SELECT
	      privilege	 as  well,  since  it  must reference table columns to
	      determine which rows to update, and/or to compute new values for
	      columns.)	  SELECT  ... FOR UPDATE and SELECT ... FOR SHARE also
	      require this privilege, in addition to the SELECT privilege. For
	      sequences, this privilege allows the use of the nextval and set-
	      val functions.

       DELETE Allows DELETE [delete(7)] of a row  from	the  specified	table.
	      (In  practice, any nontrivial DELETE command will require SELECT
	      privilege as well, since it  must	 reference  table  columns  to
	      determine which rows to delete.)

       RULE   Allows the creation of a rule on the table/view. (See the CREATE
	      RULE [create_rule(7)] statement.)

       REFERENCES
	      To create a foreign key constraint, it is necessary to have this
	      privilege on both the referencing and referenced tables.

       TRIGGER
	      Allows  the  creation  of a trigger on the specified table. (See
	      the CREATE TRIGGER [create_trigger(7)] statement.)

       CREATE For databases, allows new	 schemas  to  be  created  within  the
	      database.

	      For schemas, allows new objects to be created within the schema.
	      To rename an existing object, you must own the object  and  have
	      this privilege for the containing schema.

	      For  tablespaces, allows tables and indexes to be created within
	      the tablespace, and allows databases to be created that have the
	      tablespace as their default tablespace. (Note that revoking this
	      privilege will not alter the placement of existing objects.)

       TEMPORARY

       TEMP   Allows temporary tables to be created while using the  specified
	      database.

       EXECUTE
	      Allows  the  use	of  the	 specified function and the use of any
	      operators that are implemented on top of the function.  This  is
	      the  only	 type  of  privilege  that is applicable to functions.
	      (This syntax works for aggregate functions, as well.)

       USAGE  For procedural languages, allows the use of the  specified  lan-
	      guage  for  the  creation of functions in that language. This is
	      the only type of privilege that is applicable to procedural lan-
	      guages.

	      For schemas, allows access to objects contained in the specified
	      schema (assuming that the objects'  own  privilege  requirements
	      are  also	 met).	Essentially  this allows the grantee to ''look
	      up'' objects within the schema.

       ALL PRIVILEGES
	      Grant all of the available privileges at once.   The  PRIVILEGES
	      key  word	 is  optional  in PostgreSQL, though it is required by
	      strict SQL.

       The privileges required by other commands are listed on	the  reference
       page of the respective command.

   GRANT ON ROLES
       This variant of the GRANT command grants membership in a role to one or
       more other roles. Membership in a role is significant because  it  con-
       veys the privileges granted to a role to each of its members.

       If WITH ADMIN OPTION is specified, the member may in turn grant member-
       ship in the role to others, and revoke membership in the role as	 well.
       Without	the  admin  option,  ordinary  users  cannot do that. However,
       database superusers can grant or revoke membership in any role to  any-
       one.   Roles having CREATEROLE privilege can grant or revoke membership
       in any role that is not a superuser.

       Unlike the case with privileges, membership in a role cannot be granted
       to  PUBLIC.  Note also that this form of the command does not allow the
       noise word GROUP.

NOTES
       The REVOKE [revoke(7)] command is used to revoke access privileges.

       When a non-owner of an object  attempts	to  GRANT  privileges  on  the
       object,	the  command  will fail outright if the user has no privileges
       whatsoever on the object. As long as some privilege is  available,  the
       command will proceed, but it will grant only those privileges for which
       the user has grant options. The GRANT ALL PRIVILEGES forms will issue a
       warning	message	 if  no	 grant options are held, while the other forms
       will issue a warning if grant options for any of the privileges specif-
       ically  named  in the command are not held.  (In principle these state-
       ments apply to the object owner as well, but since the owner is	always
       treated as holding all grant options, the cases can never occur.)

       It  should  be  noted  that  database superusers can access all objects
       regardless of object privilege settings.	 This  is  comparable  to  the
       rights  of root in a Unix system.  As with root, it's unwise to operate
       as a superuser except when absolutely necessary.

       If a superuser chooses to issue a GRANT or REVOKE command, the  command
       is  performed  as  though  it  were issued by the owner of the affected
       object. In particular, privileges  granted  via	such  a	 command  will
       appear to have been granted by the object owner.	 (For role membership,
       the membership appears to have been  granted  by	 the  containing  role
       itself.)

       GRANT  and  REVOKE  can also be done by a role that is not the owner of
       the affected object, but is a member of the role that owns the  object,
       or is a member of a role that holds privileges WITH GRANT OPTION on the
       object. In this case the privileges will be  recorded  as  having  been
       granted	by  the role that actually owns the object or holds the privi-
       leges WITH GRANT OPTION. For example, if table t1 is owned by role  g1,
       of which role u1 is a member, then u1 can grant privileges on t1 to u2,
       but those privileges will appear to have been granted directly  by  g1.
       Any other member of role g1 could revoke them later.

       If  the	role  executing GRANT holds the required privileges indirectly
       via more than one role membership path, it is  unspecified  which  con-
       taining	role  will be recorded as having done the grant. In such cases
       it is best practice to use SET ROLE to become  the  specific  role  you
       want to do the GRANT as.

       Currently,  PostgreSQL does not support granting or revoking privileges
       for individual columns of a table.  One possible workaround is to  cre-
       ate a view having just the desired columns and then grant privileges to
       that view.

       Use psql(1)'s \z command to obtain information  about  existing	privi-
       leges, for example:

       => \z mytable

			       Access privileges for database "lusitania"
	Schema |  Name	 | Type	 |		       Access privileges
       --------+---------+-------+------------------------------------------------------------
	public | mytable | table | {miriam=arwdRxt/miriam,=r/miriam,"group todos=arw/miriam"}
       (1 row)

       The entries shown by \z are interpreted thus:

		     =xxxx -- privileges granted to PUBLIC
		uname=xxxx -- privileges granted to a user
	  group gname=xxxx -- privileges granted to a group

			 r -- SELECT ("read")
			 w -- UPDATE ("write")
			 a -- INSERT ("append")
			 d -- DELETE
			 R -- RULE
			 x -- REFERENCES
			 t -- TRIGGER
			 X -- EXECUTE
			 U -- USAGE
			 C -- CREATE
			 T -- TEMPORARY
		   arwdRxt -- ALL PRIVILEGES (for tables)
			 * -- grant option for preceding privilege

		     /yyyy -- user who granted this privilege

       The  above  example display would be seen by user miriam after creating
       table mytable and doing

       GRANT SELECT ON mytable TO PUBLIC;
       GRANT SELECT, UPDATE, INSERT ON mytable TO GROUP todos;


       If the ''Access privileges'' column is empty for	 a  given  object,  it
       means the object has default privileges (that is, its privileges column
       is null). Default privileges always  include  all  privileges  for  the
       owner,  and  may	 include  some	privileges for PUBLIC depending on the
       object type, as explained above. The first GRANT or REVOKE on an object
       will  instantiate  the  default	privileges  (producing,	 for  example,
       {miriam=arwdRxt/miriam})	 and  then  modify  them  per  the   specified
       request.

       Notice  that  the  owner's implicit grant options are not marked in the
       access privileges display. A * will appear only when grant options have
       been explicitly granted to someone.

EXAMPLES
       Grant insert privilege to all users on table films:

       GRANT INSERT ON films TO PUBLIC;


       Grant all available privileges to user manuel on view kinds:

       GRANT ALL PRIVILEGES ON kinds TO manuel;

       Note  that while the above will indeed grant all privileges if executed
       by a superuser or the owner of kinds, when executed by someone else  it
       will  only grant those permissions for which the someone else has grant
       options.

       Grant membership in role admins to user joe:

       GRANT admins TO joe;


COMPATIBILITY
       According to the SQL standard, the PRIVILEGES key word  in  ALL	PRIVI-
       LEGES is required. The SQL standard does not support setting the privi-
       leges on more than one object per command.

       PostgreSQL allows an object owner to revoke  his	 own  ordinary	privi-
       leges:  for example, a table owner can make the table read-only to him-
       self by revoking his own INSERT, UPDATE, and DELETE privileges. This is
       not  possible  according	 to the SQL standard. The reason is that Post-
       greSQL treats the owner's privileges as	having	been  granted  by  the
       owner  to  himself;  therefore he can revoke them too. In the SQL stan-
       dard, the owner's privileges are granted by an assumed  entity  ''_SYS-
       TEM''. Not being ''_SYSTEM'', the owner cannot revoke these rights.

       The  SQL	 standard  allows  setting  privileges	for individual columns
       within a table:

       GRANT privileges
	   ON table [ ( column [, ...] ) ] [, ...]
	   TO { PUBLIC | username [, ...] } [ WITH GRANT OPTION ]


       The SQL standard provides for a	USAGE  privilege  on  other  kinds  of
       objects: character sets, collations, translations, domains.

       The  RULE privilege, and privileges on databases, tablespaces, schemas,
       languages, and sequences are PostgreSQL extensions.

SEE ALSO
       REVOKE [revoke(7)]



SQL - Language Statements	  2010-12-14			       GRANT()
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