set_session_authorization(7) [suse man page]

SET SESSION 
AUTHORIZATION(7)					   SQL Commands 				      SET SESSION AUTHORIZATION(7)

NAME

       SET SESSION AUTHORIZATION - set the session user identifier and the current user identifier of the current session

SYNOPSIS

       SET [ SESSION | LOCAL ] SESSION AUTHORIZATION username
       SET [ SESSION | LOCAL ] SESSION AUTHORIZATION DEFAULT
       RESET SESSION AUTHORIZATION

DESCRIPTION

       This  command sets the session user identifier and the current user identifier of the current SQL session to be username. The user name can
       be written as either an identifier or a string literal. Using this command, it is possible, for example, to temporarily become an  unprivi-
       leged user and later switch back to being a superuser.

       The  session user identifier is initially set to be the (possibly authenticated) user name provided by the client. The current user identi-
       fier is normally equal to the session user identifier, but might change temporarily in the context of SECURITY DEFINER functions and  simi-
       lar mechanisms; it can also be changed by SET ROLE [set_role(7)].  The current user identifier is relevant for permission checking.

       The  session  user  identifier can be changed only if the initial session user (the authenticated user) had the superuser privilege. Other-
       wise, the command is accepted only if it specifies the authenticated user name.

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

       The DEFAULT and RESET forms reset the session and current user identifiers to be the originally authenticated user name. These forms can be
       executed by any user.

NOTES

       SET SESSION AUTHORIZATION cannot be used within a SECURITY DEFINER function.

EXAMPLES

       SELECT SESSION_USER, CURRENT_USER;

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

       SET SESSION AUTHORIZATION 'paul';

       SELECT SESSION_USER, CURRENT_USER;

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

COMPATIBILITY

       The SQL standard allows some other expressions to appear in place of the literal username, but these options are not important in practice.
       PostgreSQL allows identifier syntax ("username"), which SQL does not. 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 syn-
       tax.

       The privileges necessary to execute this command are left implementation-defined by the standard.

SEE ALSO

       SET ROLE [set_role(7)]

SQL - Language Statements					    2010-05-14					      SET SESSION AUTHORIZATION(7)

SET 
ROLE(7)						  PostgreSQL 9.2.7 Documentation					       SET ROLE(7)

NAME

       SET_ROLE - set the current user identifier of the current session

SYNOPSIS

       SET [ SESSION | LOCAL ] ROLE role_name
       SET [ SESSION | LOCAL ] ROLE NONE
       RESET ROLE

DESCRIPTION

       This command sets the current user identifier of the current SQL session to be role_name. The role name can be written as either an
       identifier 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 role_name 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(7) command.

       The NONE and RESET forms reset the current user identifier to be the current session user identifier. These forms can 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 session 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_SESSION_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 does not process session variables as specified by the role's ALTER ROLE (ALTER_ROLE(7)) settings; this only happens during login.

       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 standard 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))

PostgreSQL 9.2.7						    2014-02-17							       SET ROLE(7)