<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >ALTER DOMAIN</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 8.0.11 Documentation" HREF="index.html"><LINK REL="UP" TITLE="SQL Commands" HREF="sql-commands.html"><LINK REL="PREVIOUS" TITLE="ALTER DATABASE" HREF="sql-alterdatabase.html"><LINK REL="NEXT" TITLE="ALTER FUNCTION" HREF="sql-alterfunction.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2007-02-02T03:57:22"></HEAD ><BODY CLASS="REFENTRY" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" >PostgreSQL 8.0.11 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-alterdatabase.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-alterdatabase.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="sql-alterfunction.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="sql-alterfunction.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SQL-ALTERDOMAIN" ></A >ALTER DOMAIN</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN36494" ></A ><H2 >Name</H2 > ALTER DOMAIN -- change the definition of a domain </DIV ><A NAME="AEN36497" ></A ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN36499" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > { SET DEFAULT <TT CLASS="REPLACEABLE" ><I >expression</I ></TT > | DROP DEFAULT } ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > { SET | DROP } NOT NULL ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > ADD <TT CLASS="REPLACEABLE" ><I >domain_constraint</I ></TT > ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > DROP CONSTRAINT <TT CLASS="REPLACEABLE" ><I >constraint_name</I ></TT > [ RESTRICT | CASCADE ] ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > OWNER TO <TT CLASS="REPLACEABLE" ><I >new_owner</I ></TT > </PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN36510" ></A ><H2 >Description</H2 ><P > <TT CLASS="COMMAND" >ALTER DOMAIN</TT > changes the definition of an existing domain. There are several sub-forms: </P ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT >SET/DROP DEFAULT</DT ><DD ><P > These forms set or remove the default value for a domain. Note that defaults only apply to subsequent <TT CLASS="COMMAND" >INSERT</TT > commands; they do not affect rows already in a table using the domain. </P ></DD ><DT >SET/DROP NOT NULL</DT ><DD ><P > These forms change whether a domain is marked to allow NULL values or to reject NULL values. You may only <TT CLASS="LITERAL" >SET NOT NULL</TT > when the columns using the domain contain no null values. </P ></DD ><DT >ADD <TT CLASS="REPLACEABLE" ><I >domain_constraint</I ></TT ></DT ><DD ><P > This form adds a new constraint to a domain using the same syntax as <A HREF="sql-createdomain.html" ><I >CREATE DOMAIN</I ></A >. This will only succeed if all columns using the domain satisfy the new constraint. </P ></DD ><DT >DROP CONSTRAINT</DT ><DD ><P > This form drops constraints on a domain. </P ></DD ><DT >OWNER</DT ><DD ><P > This form changes the owner of the domain to the specified user. </P ></DD ></DL ></DIV ><P > You must own the domain to use <TT CLASS="COMMAND" >ALTER DOMAIN</TT >; except for <TT CLASS="COMMAND" >ALTER DOMAIN OWNER</TT >, which may only be executed by a superuser. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN36542" ></A ><H2 >Parameters</H2 ><P > <P ></P ></P><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="REPLACEABLE" ><I >name</I ></TT ></DT ><DD ><P > The name (possibly schema-qualified) of an existing domain to alter. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >domain_constraint</I ></TT ></DT ><DD ><P > New domain constraint for the domain. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >constraint_name</I ></TT ></DT ><DD ><P > Name of an existing constraint to drop. </P ></DD ><DT ><TT CLASS="LITERAL" >CASCADE</TT ></DT ><DD ><P > Automatically drop objects that depend on the constraint. </P ></DD ><DT ><TT CLASS="LITERAL" >RESTRICT</TT ></DT ><DD ><P > Refuse to drop the constraint if there are any dependent objects. This is the default behavior. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >new_owner</I ></TT ></DT ><DD ><P > The user name of the new owner of the domain. </P ></DD ></DL ></DIV ><P> </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN36576" ></A ><H2 >Examples</H2 ><P > To add a <TT CLASS="LITERAL" >NOT NULL</TT > constraint to a domain: </P><PRE CLASS="PROGRAMLISTING" >ALTER DOMAIN zipcode SET NOT NULL; </PRE ><P> To remove a <TT CLASS="LITERAL" >NOT NULL</TT > constraint from a domain: </P><PRE CLASS="PROGRAMLISTING" >ALTER DOMAIN zipcode DROP NOT NULL; </PRE ><P> </P ><P > To add a check constraint to a domain: </P><PRE CLASS="PROGRAMLISTING" >ALTER DOMAIN zipcode ADD CONSTRAINT zipchk CHECK (char_length(VALUE) = 5); </PRE ><P> </P ><P > To remove a check constraint from a domain: </P><PRE CLASS="PROGRAMLISTING" >ALTER DOMAIN zipcode DROP CONSTRAINT zipchk; </PRE ><P> </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN36587" ></A ><H2 >Compatibility</H2 ><P > The <TT CLASS="COMMAND" >ALTER DOMAIN</TT > statement is compatible with SQL:1999, except for the <TT CLASS="LITERAL" >OWNER</TT > variant, which is a <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > extension. </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sql-alterdatabase.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sql-alterfunction.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >ALTER DATABASE</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >ALTER FUNCTION</TD ></TR ></TABLE ></DIV ></BODY ></HTML >