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| $PostgreSQL: pgsql/doc/src/sgml/ref/drop_type.sgml,v 1.31 2008/11/14 10:22:47 petere Exp $ |
| PostgreSQL documentation |
| --> |
| |
| <refentry id="SQL-DROPTYPE"> |
| <refmeta> |
| <refentrytitle id="SQL-DROPTYPE-TITLE">DROP TYPE</refentrytitle> |
| <manvolnum>7</manvolnum> |
| <refmiscinfo>SQL - Language Statements</refmiscinfo> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>DROP TYPE</refname> |
| <refpurpose>remove a data type</refpurpose> |
| </refnamediv> |
| |
| <indexterm zone="sql-droptype"> |
| <primary>DROP TYPE</primary> |
| </indexterm> |
| |
| <refsynopsisdiv> |
| <synopsis> |
| DROP TYPE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ CASCADE | RESTRICT ] |
| </synopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para> |
| <command>DROP TYPE</command> removes a user-defined data type. |
| Only the owner of a type can remove it. |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Parameters</title> |
| |
| <variablelist> |
| <varlistentry> |
| <term><literal>IF EXISTS</literal></term> |
| <listitem> |
| <para> |
| Do not throw an error if the type does not exist. A notice is issued |
| in this case. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><replaceable class="PARAMETER">name</replaceable></term> |
| <listitem> |
| <para> |
| The name (optionally schema-qualified) of the data type to remove. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><literal>CASCADE</literal></term> |
| <listitem> |
| <para> |
| Automatically drop objects that depend on the type (such as |
| table columns, functions, operators). |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><literal>RESTRICT</literal></term> |
| <listitem> |
| <para> |
| Refuse to drop the type if any objects depend on it. This is |
| the default. |
| </para> |
| </listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1 id="SQL-DROPTYPE-examples"> |
| <title>Examples</title> |
| |
| <para> |
| To remove the data type <type>box</type>: |
| <programlisting> |
| DROP TYPE box; |
| </programlisting> |
| </para> |
| </refsect1> |
| |
| <refsect1 id="SQL-DROPTYPE-compatibility"> |
| <title>Compatibility</title> |
| |
| <para> |
| This command is similar to the corresponding command in the SQL |
| standard, apart from the <literal>IF EXISTS</> |
| option, which is a <productname>PostgreSQL</> extension. |
| But note that the <command>CREATE TYPE</command> command |
| and the data type extension mechanisms in |
| <productname>PostgreSQL</productname> differ from the SQL standard. |
| </para> |
| </refsect1> |
| |
| <refsect1 id="SQL-DROPTYPE-see-also"> |
| <title>See Also</title> |
| |
| <simplelist type="inline"> |
| <member><xref linkend="sql-createtype" endterm="sql-createtype-title"></member> |
| <member><xref linkend="sql-altertype" endterm="sql-altertype-title"></member> |
| </simplelist> |
| </refsect1> |
| |
| </refentry> |