SET ROLE()			 SQL Commands			    SET ROLE()



NAME
       SET ROLE - set the current user identifier of the current session


SYNOPSIS
       SET [ SESSION | LOCAL ] ROLE rolename
       SET [ SESSION | LOCAL ] ROLE NONE
       RESET ROLE


DESCRIPTION
       This  command  sets the current user identifier of the current SQL ses-
       sion to be rolename. The role name may be written as either an  identi-
       fier or a string literal.  After SET ROLE, permissions checking for SQL
       commands is carried out as though the named role were the one that  had
       logged in originally.

       The  specified rolename must be a role that the current session user is
       a member of.  (If the session user is a	superuser,  any	 role  can  be
       selected.)

       The  SESSION  and  LOCAL	 modifiers act the same as for the regular SET
       [set(7)] command.

       The NONE and RESET forms reset the current user identifier  to  be  the
       current	session	 user  identifier.  These forms may be executed by any
       user.

NOTES
       Using this command, it is possible to either add privileges or restrict
       one's  privileges. If the session user role has the INHERITS attribute,
       then it automatically has all the privileges  of	 every	role  that  it
       could  SET  ROLE	 to;  in  this case SET ROLE effectively drops all the
       privileges assigned directly to the session user and to the other roles
       it  is  a member of, leaving only the privileges available to the named
       role. On the other hand, if the session user role  has  the  NOINHERITS
       attribute,  SET ROLE drops the privileges assigned directly to the ses-
       sion user and instead acquires the privileges available	to  the	 named
       role.

       In  particular, when a superuser chooses to SET ROLE to a non-superuser
       role, she loses her superuser privileges.

       SET ROLE has effects comparable to SET SESSION AUTHORIZATION  [set_ses-
       sion_authorization(7)],	but  the  privilege  checks involved are quite
       different. Also, SET SESSION AUTHORIZATION determines which  roles  are
       allowable  for later SET ROLE commands, whereas changing roles with SET
       ROLE does not change the set of roles allowed to a later SET ROLE.

       SET ROLE cannot be used within a SECURITY DEFINER function.

EXAMPLES
       SELECT SESSION_USER, CURRENT_USER;

	session_user | current_user
       --------------+--------------
	peter	     | peter

       SET ROLE 'paul';

       SELECT SESSION_USER, CURRENT_USER;

	session_user | current_user
       --------------+--------------
	peter	     | paul


COMPATIBILITY
       PostgreSQL allows identifier syntax ("rolename"), while the  SQL	 stan-
       dard requires the role name to be written as a string literal. SQL does
       not allow this command during a transaction; PostgreSQL does  not  make
       this  restriction because there is no reason to.	 The SESSION and LOCAL
       modifiers are a PostgreSQL extension, as is the RESET syntax.

SEE ALSO
       SET SESSION AUTHORIZATION [set_session_authorization(7)]



SQL - Language Statements	  2010-12-14			    SET ROLE()