<!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 9.6.19 Documentation" HREF="index.html"><LINK REL="UP" TITLE="SQL Commands" HREF="sql-commands.html"><LINK REL="PREVIOUS" TITLE="ALTER DEFAULT PRIVILEGES" HREF="sql-alterdefaultprivileges.html"><LINK REL="NEXT" TITLE="ALTER EVENT TRIGGER" HREF="sql-altereventtrigger.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="2020-09-02T07:27:19"></HEAD ><BODY CLASS="REFENTRY" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="4" ALIGN="center" VALIGN="bottom" ><A HREF="index.html" >PostgreSQL 9.6.19 Documentation</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A TITLE="ALTER DEFAULT PRIVILEGES" HREF="sql-alterdefaultprivileges.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="ALTER EVENT TRIGGER" HREF="sql-altereventtrigger.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="AEN73153" ></A ><H2 >Name</H2 >ALTER DOMAIN -- change the definition of a domain </DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN73156" ></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 > [ NOT VALID ] ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > DROP CONSTRAINT [ IF EXISTS ] <TT CLASS="REPLACEABLE" ><I >constraint_name</I ></TT > [ RESTRICT | CASCADE ] ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > RENAME CONSTRAINT <TT CLASS="REPLACEABLE" ><I >constraint_name</I ></TT > TO <TT CLASS="REPLACEABLE" ><I >new_constraint_name</I ></TT > ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > VALIDATE CONSTRAINT <TT CLASS="REPLACEABLE" ><I >constraint_name</I ></TT > ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > OWNER TO { <TT CLASS="REPLACEABLE" ><I >new_owner</I ></TT > | CURRENT_USER | SESSION_USER } ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > RENAME TO <TT CLASS="REPLACEABLE" ><I >new_name</I ></TT > ALTER DOMAIN <TT CLASS="REPLACEABLE" ><I >name</I ></TT > SET SCHEMA <TT CLASS="REPLACEABLE" ><I >new_schema</I ></TT ></PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN73176" ></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 can 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 > [ NOT VALID ]</DT ><DD ><P > This form adds a new constraint to a domain using the same syntax as <A HREF="sql-createdomain.html" >CREATE DOMAIN</A >. When a new constraint is added to a domain, all columns using that domain will be checked against the newly added constraint. These checks can be suppressed by adding the new constraint using the <TT CLASS="LITERAL" >NOT VALID</TT > option; the constraint can later be made valid using <TT CLASS="COMMAND" >ALTER DOMAIN ... VALIDATE CONSTRAINT</TT >. Newly inserted or updated rows are always checked against all constraints, even those marked <TT CLASS="LITERAL" >NOT VALID</TT >. <TT CLASS="LITERAL" >NOT VALID</TT > is only accepted for <TT CLASS="LITERAL" >CHECK</TT > constraints. </P ></DD ><DT >DROP CONSTRAINT [ IF EXISTS ]</DT ><DD ><P > This form drops constraints on a domain. If <TT CLASS="LITERAL" >IF EXISTS</TT > is specified and the constraint does not exist, no error is thrown. In this case a notice is issued instead. </P ></DD ><DT >RENAME CONSTRAINT</DT ><DD ><P > This form changes the name of a constraint on a domain. </P ></DD ><DT >VALIDATE CONSTRAINT</DT ><DD ><P > This form validates a constraint previously added as <TT CLASS="LITERAL" >NOT VALID</TT >, that is, it verifies that all values in table columns of the domain type satisfy the specified constraint. </P ></DD ><DT >OWNER</DT ><DD ><P > This form changes the owner of the domain to the specified user. </P ></DD ><DT ><TT CLASS="LITERAL" >RENAME</TT ></DT ><DD ><P > This form changes the name of the domain. </P ></DD ><DT >SET SCHEMA</DT ><DD ><P > This form changes the schema of the domain. Any constraints associated with the domain are moved into the new schema as well. </P ></DD ></DL ></DIV ><P > You must own the domain to use <TT CLASS="COMMAND" >ALTER DOMAIN</TT >. To change the schema of a domain, you must also have <TT CLASS="LITERAL" >CREATE</TT > privilege on the new schema. To alter the owner, you must also be a direct or indirect member of the new owning role, and that role must have <TT CLASS="LITERAL" >CREATE</TT > privilege on the domain's schema. (These restrictions enforce that altering the owner doesn't do anything you couldn't do by dropping and recreating the domain. However, a superuser can alter ownership of any domain anyway.) </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN73233" ></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 or rename. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >NOT VALID</I ></TT ></DT ><DD ><P > Do not verify existing stored data for constraint validity. </P ></DD ><DT ><TT CLASS="LITERAL" >CASCADE</TT ></DT ><DD ><P > Automatically drop objects that depend on the constraint, and in turn all objects that depend on those objects (see <A HREF="ddl-depend.html" >Section 5.13</A >). </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_name</I ></TT ></DT ><DD ><P > The new name for the domain. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >new_constraint_name</I ></TT ></DT ><DD ><P > The new name for the constraint. </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 ><DT ><TT CLASS="REPLACEABLE" ><I >new_schema</I ></TT ></DT ><DD ><P > The new schema for the domain. </P ></DD ></DL ></DIV ><P> </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN73288" ></A ><H2 >Notes</H2 ><P > Although <TT CLASS="COMMAND" >ALTER DOMAIN ADD CONSTRAINT</TT > attempts to verify that existing stored data satisfies the new constraint, this check is not bulletproof, because the command cannot <SPAN CLASS="QUOTE" >"see"</SPAN > table rows that are newly inserted or updated and not yet committed. If there is a hazard that concurrent operations might insert bad data, the way to proceed is to add the constraint using the <TT CLASS="LITERAL" >NOT VALID</TT > option, commit that command, wait until all transactions started before that commit have finished, and then issue <TT CLASS="COMMAND" >ALTER DOMAIN VALIDATE CONSTRAINT</TT > to search for data violating the constraint. This method is reliable because once the constraint is committed, all new transactions are guaranteed to enforce it against new values of the domain type. </P ><P > Currently, <TT CLASS="COMMAND" >ALTER DOMAIN ADD CONSTRAINT</TT >, <TT CLASS="COMMAND" >ALTER DOMAIN VALIDATE CONSTRAINT</TT >, and <TT CLASS="COMMAND" >ALTER DOMAIN SET NOT NULL</TT > will fail if the validated named domain or any derived domain is used within a composite-type column of any table in the database. They should eventually be improved to be able to verify the new constraint for such nested columns. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN73299" ></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 ><P > To rename a check constraint on a domain: </P><PRE CLASS="PROGRAMLISTING" >ALTER DOMAIN zipcode RENAME CONSTRAINT zipchk TO zip_check;</PRE ><P> </P ><P > To move the domain into a different schema: </P><PRE CLASS="PROGRAMLISTING" >ALTER DOMAIN zipcode SET SCHEMA customers;</PRE ><P></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SQL-ALTERDOMAIN-COMPATIBILITY" ></A ><H2 >Compatibility</H2 ><P > <TT CLASS="COMMAND" >ALTER DOMAIN</TT > conforms to the <ACRONYM CLASS="ACRONYM" >SQL</ACRONYM > standard, except for the <TT CLASS="LITERAL" >OWNER</TT >, <TT CLASS="LITERAL" >RENAME</TT >, <TT CLASS="LITERAL" >SET SCHEMA</TT >, and <TT CLASS="LITERAL" >VALIDATE CONSTRAINT</TT > variants, which are <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > extensions. The <TT CLASS="LITERAL" >NOT VALID</TT > clause of the <TT CLASS="LITERAL" >ADD CONSTRAINT</TT > variant is also a <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > extension. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="SQL-ALTERDOMAIN-SEE-ALSO" ></A ><H2 >See Also</H2 ><A HREF="sql-createdomain.html" >CREATE DOMAIN</A >, <A HREF="sql-dropdomain.html" >DROP DOMAIN</A ></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-alterdefaultprivileges.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-altereventtrigger.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >ALTER DEFAULT PRIVILEGES</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 EVENT TRIGGER</TD ></TR ></TABLE ></DIV ></BODY ></HTML >