SET(7)								   SQL Commands 							    SET(7)

NAME

       SET - change a run-time parameter

SYNOPSIS

       SET [ SESSION | LOCAL ] variable { TO | = } { value | 'value' | DEFAULT }
       SET [ SESSION | LOCAL ] TIME ZONE { timezone | LOCAL | DEFAULT }

   INPUTS
       SESSION
	      Specifies that the command takes effect for the current session.	(This is the default if neither SESSION nor LOCAL appears.)

       LOCAL  Specifies  that the command takes effect for only the current transaction. After COMMIT or ROLLBACK, the session-level setting takes
	      effect again. Note that SET LOCAL will appear to have no effect if it's executed outside a BEGIN block, since the  transaction  will
	      end immediately.

       variable
	      A settable run-time parameter.

       value  New  value  of parameter. DEFAULT can be used to specify resetting the parameter to its default value. Lists of strings are allowed,
	      but more complex constructs may need to be single or double quoted.

DESCRIPTION

       The SET command changes run-time configuration parameters. Many of the run-time parameters listed  in  the  Administrator's  Guide  can	be
       changed on-the-fly with SET. (But some require superuser privileges to change, and others cannot be changed after server or session start.)
       Note that SET only affects the value used by the current session.

       If SET or SET SESSION is issued within a transaction that is later aborted, the effects of the SET command disappear when  the  transaction
       is  rolled  back.  (This  behavior  represents a change from PostgreSQL versions prior to 7.3, where the effects of SET would not roll back
       after a later error.) Once the surrounding transaction is committed, the effects will persist until the end of the session, unless overrid-
       den by another SET.

       The effects of SET LOCAL last only till the end of the current transaction, whether committed or not. A special case is SET followed by SET
       LOCAL within a single transaction: the SET LOCAL value will be seen until the end of the transaction, but afterwards (if the transaction is
       committed) the SET value will take effect.

       Even  with  autocommit  set to off, SET does not start a new transaction block. See the autocommit section of the Administrator's Guide for
       details.

       Here are additional details about a few of the parameters that can be set:

       DATESTYLE
	      Choose the date/time representation style. Two separate settings are involved: the default date/time output and  the  interpretation
	      of ambiguous input.

	      The following are date/time output styles:

	      ISO    Use ISO 8601-style dates and times (YYYY-MM-DD HH:MM:SS). This is the default.

	      SQL    Use Oracle/Ingres-style dates and times. Note that this style has nothing to do with SQL (which mandates ISO 8601 style), the
		     naming of this option is a historical accident.

	      PostgreSQL
		     Use traditional PostgreSQL format.

	      German Use dd.mm.yyyy for numeric date representations.

       The following two options determine both a substyle of the ``SQL'' and ``PostgreSQL'' output formats and the  preferred	interpretation	of
       ambiguous date input.

	      European
		     Use dd/mm/yyyy for numeric date representations.

	      NonEuropean

	      US     Use mm/dd/yyyy for numeric date representations.

       A  value  for SET DATESTYLE can be one from the first list (output styles), or one from the second list (substyles), or one from each sepa-
       rated by a comma.

       SET DATESTYLE affects interpretation of input and provides several standard output formats. For applications needing  different	variations
       or tighter control over input or output, consider using the to_char family of functions.

       There  are  several now-deprecated means for setting the date style in addition to the normal methods of setting it via SET or a configura-
       tion-file entry:

       Setting the postmaster's PGDATESTYLE environment variable. (This will be overridden by any of the other methods.)

       Running postmaster using the option -o -e to set dates to the European convention.  (This overrides environment	variables  and	configura-
       tion-file entries.)

       Setting the client's PGDATESTYLE environment variable.  If PGDATESTYLE is set in the frontend environment of a client based on libpq, libpq
       will automatically set DATESTYLE to the value of PGDATESTYLE during connection start-up. This is equivalent to a manually issued  SET  DAT-
       ESTYLE.

       NAMES  SET NAMES is an alias for SET CLIENT_ENCODING.

       SEED   Sets the internal seed for the random number generator.

	      value  The  value  for  the seed to be used by the random function. Allowed values are floating-point numbers between 0 and 1, which
		     are then multiplied by 231-1.

       The seed can also be set by invoking the setseed SQL function:

       SELECT setseed(value);

       SERVER_ENCODING
	      Shows the server-side multibyte encoding. (At present, this parameter can be shown but not set, because the encoding  is	determined
	      at initdb time.)

       TIME ZONE

       TIMEZONE
	      Sets  the  default  time	zone for your session. Arguments can be an SQL time interval constant, an integer or double precision con-
	      stant, or a string representing a time zone name recognized by the host operating system.

	      Here are some typical values for time zone settings:

	      'PST8PDT'
		     Set the time zone for Berkeley, California.

	      'Portugal'
		     Set the time zone for Portugal.

	      'Europe/Rome'
		     Set the time zone for Italy.

	      7      Set the time zone to 7 hours offset west from GMT (equivalent to PDT).

	      INTERVAL '08:00' HOUR TO MINUTE
		     Set the time zone to 8 hours offset west from GMT (equivalent to PST).

	      LOCAL

	      DEFAULT
		     Set the time zone to your local time zone (the one that your operating system defaults to).

       The available time zone names depend on your operating system. For example, on Linux /usr/share/zoneinfo  contains  the	database  of  time
       zones; the names of the files in that directory can be used as parameters to this command.

       If an invalid time zone is specified, the time zone becomes GMT (on most systems anyway).

       If  the	PGTZ  environment variable is set in the frontend environment of a client based on libpq, libpq will automatically SET TIMEZONE to
       the value of PGTZ during connection start-up.

       Use SHOW [show(7)] to show the current setting of a parameter.

DIAGNOSTICS

       SET    Message returned if successful.

       ERROR: 'name is not a
	      The parameter you tried to set does not exist.

       ERROR: 'name':
	      You must be a superuser to alter certain settings.

       ERROR: 'name' cannot
	      Some parameters are fixed once the server is started.

EXAMPLES

       Set the style of date to traditional PostgreSQL with European conventions:

       SET DATESTYLE TO PostgreSQL,European;

       Set the time zone for Berkeley, California, using quotes to preserve the uppercase spelling of the time zone name (note that the date style
       is PostgreSQL for this example):

       SET TIME ZONE 'PST8PDT';
       SELECT CURRENT_TIMESTAMP AS today;
		      today
       ------------------------------------
	Tue Feb 26 07:32:21.42834 2002 PST

       Set the time zone for Italy (note the required single quotes to handle the special characters):

       SET TIME ZONE 'Europe/Rome';
       SELECT CURRENT_TIMESTAMP AS today;

		    today
       -------------------------------
	2002-10-08 05:39:35.008271+02

COMPATIBILITY

   SQL92
       SET TIME ZONE extends syntax defined in SQL9x. SQL9x allows only numeric time zone offsets while PostgreSQL allows full time zone specifier
       strings as well. All other SET features are PostgreSQL extensions.

SEE ALSO

       The function set_config provides the equivalent capability. See Miscellaneous Functions in the PostgreSQL User's Guide.

SQL - Language Statements					    2002-11-22								    SET(7)