| <!-- |
| $PostgreSQL: pgsql/doc/src/sgml/ref/alter_domain.sgml,v 1.24 2008/11/14 10:22:45 petere Exp $ |
| PostgreSQL documentation |
| --> |
| |
| <refentry id="SQL-ALTERDOMAIN"> |
| <refmeta> |
| <refentrytitle id="sql-alterdomain-title">ALTER DOMAIN</refentrytitle> |
| <manvolnum>7</manvolnum> |
| <refmiscinfo>SQL - Language Statements</refmiscinfo> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>ALTER DOMAIN</refname> |
| <refpurpose> |
| change the definition of a domain |
| </refpurpose> |
| </refnamediv> |
| |
| <indexterm zone="sql-alterdomain"> |
| <primary>ALTER DOMAIN</primary> |
| </indexterm> |
| |
| <refsynopsisdiv> |
| <synopsis> |
| ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable> |
| { SET DEFAULT <replaceable class="PARAMETER">expression</replaceable> | DROP DEFAULT } |
| ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable> |
| { SET | DROP } NOT NULL |
| ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable> |
| ADD <replaceable class="PARAMETER">domain_constraint</replaceable> |
| ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable> |
| DROP CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> [ RESTRICT | CASCADE ] |
| ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable> |
| OWNER TO <replaceable class="PARAMETER">new_owner</replaceable> |
| ALTER DOMAIN <replaceable class="PARAMETER">name</replaceable> |
| SET SCHEMA <replaceable class="PARAMETER">new_schema</replaceable> |
| </synopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para> |
| <command>ALTER DOMAIN</command> changes the definition of an existing domain. |
| There are several sub-forms: |
| </para> |
| |
| <variablelist> |
| <varlistentry> |
| <term>SET/DROP DEFAULT</term> |
| <listitem> |
| <para> |
| These forms set or remove the default value for a domain. Note |
| that defaults only apply to subsequent <command>INSERT</command> |
| commands; they do not affect rows already in a table using the domain. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term>SET/DROP NOT NULL</term> |
| <listitem> |
| <para> |
| These forms change whether a domain is marked to allow NULL |
| values or to reject NULL values. You can only <literal>SET NOT NULL</> |
| when the columns using the domain contain no null values. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term>ADD <replaceable class="PARAMETER">domain_constraint</replaceable></term> |
| <listitem> |
| <para> |
| This form adds a new constraint to a domain using the same syntax as |
| <xref linkend="SQL-CREATEDOMAIN" endterm="SQL-CREATEDOMAIN-TITLE">. |
| This will only succeed if all columns using the domain satisfy the |
| new constraint. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term>DROP CONSTRAINT</term> |
| <listitem> |
| <para> |
| This form drops constraints on a domain. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term>OWNER</term> |
| <listitem> |
| <para> |
| This form changes the owner of the domain to the specified user. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term>SET SCHEMA</term> |
| <listitem> |
| <para> |
| This form changes the schema of the domain. Any constraints |
| associated with the domain are moved into the new schema as well. |
| </para> |
| </listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <para> |
| You must own the domain to use <command>ALTER DOMAIN</>. |
| To change the schema of a domain, you must also have |
| <literal>CREATE</literal> 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 <literal>CREATE</literal> 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.) |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Parameters</title> |
| |
| <para> |
| <variablelist> |
| <varlistentry> |
| <term><replaceable class="PARAMETER">name</replaceable></term> |
| <listitem> |
| <para> |
| The name (possibly schema-qualified) of an existing domain to |
| alter. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><replaceable class="PARAMETER">domain_constraint</replaceable></term> |
| <listitem> |
| <para> |
| New domain constraint for the domain. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><replaceable class="PARAMETER">constraint_name</replaceable></term> |
| <listitem> |
| <para> |
| Name of an existing constraint to drop. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><literal>CASCADE</literal></term> |
| <listitem> |
| <para> |
| Automatically drop objects that depend on the constraint. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><literal>RESTRICT</literal></term> |
| <listitem> |
| <para> |
| Refuse to drop the constraint if there are any dependent |
| objects. This is the default behavior. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><replaceable class="PARAMETER">new_owner</replaceable></term> |
| <listitem> |
| <para> |
| The user name of the new owner of the domain. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><replaceable class="PARAMETER">new_schema</replaceable></term> |
| <listitem> |
| <para> |
| The new schema for the domain. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| </variablelist> |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Notes</title> |
| |
| <para> |
| Currently, <command>ALTER DOMAIN ADD CONSTRAINT</> and |
| <command>ALTER DOMAIN SET NOT NULL</> will fail if the 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. |
| </para> |
| |
| </refsect1> |
| |
| <refsect1> |
| <title>Examples</title> |
| |
| <para> |
| To add a <literal>NOT NULL</literal> constraint to a domain: |
| <programlisting> |
| ALTER DOMAIN zipcode SET NOT NULL; |
| </programlisting> |
| To remove a <literal>NOT NULL</literal> constraint from a domain: |
| <programlisting> |
| ALTER DOMAIN zipcode DROP NOT NULL; |
| </programlisting> |
| </para> |
| |
| <para> |
| To add a check constraint to a domain: |
| <programlisting> |
| ALTER DOMAIN zipcode ADD CONSTRAINT zipchk CHECK (char_length(VALUE) = 5); |
| </programlisting> |
| </para> |
| |
| <para> |
| To remove a check constraint from a domain: |
| <programlisting> |
| ALTER DOMAIN zipcode DROP CONSTRAINT zipchk; |
| </programlisting> |
| </para> |
| |
| <para> |
| To move the domain into a different schema: |
| <programlisting> |
| ALTER DOMAIN zipcode SET SCHEMA customers; |
| </programlisting> |
| </para> |
| </refsect1> |
| |
| <refsect1 id="SQL-ALTERDOMAIN-compatibility"> |
| <title>Compatibility</title> |
| |
| <para> |
| <command>ALTER DOMAIN</command> conforms to the <acronym>SQL</acronym> |
| standard, |
| except for the <literal>OWNER</> and <literal>SET SCHEMA</> variants, |
| which are <productname>PostgreSQL</productname> extensions. |
| </para> |
| </refsect1> |
| |
| <refsect1 id="SQL-ALTERDOMAIN-see-also"> |
| <title>See Also</title> |
| |
| <simplelist type="inline"> |
| <member><xref linkend="sql-createdomain" endterm="sql-createdomain-title"></member> |
| <member><xref linkend="sql-dropdomain" endterm="sql-dropdomain-title"></member> |
| </simplelist> |
| </refsect1> |
| |
| </refentry> |