| <!-- $PostgreSQL: pgsql/doc/src/sgml/ref/drop_cast.sgml,v 1.8 2006/09/16 00:30:18 momjian Exp $ --> |
| |
| <refentry id="SQL-DROPCAST"> |
| <refmeta> |
| <refentrytitle id="SQL-DROPCAST-TITLE">DROP CAST</refentrytitle> |
| <refmiscinfo>SQL - Language Statements</refmiscinfo> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>DROP CAST</refname> |
| <refpurpose>remove a cast</refpurpose> |
| </refnamediv> |
| |
| <indexterm zone="sql-dropcast"> |
| <primary>DROP CAST</primary> |
| </indexterm> |
| |
| <refsynopsisdiv> |
| <synopsis> |
| DROP CAST [ IF EXISTS ] (<replaceable>sourcetype</replaceable> AS <replaceable>targettype</replaceable>) [ CASCADE | RESTRICT ] |
| </synopsis> |
| </refsynopsisdiv> |
| |
| <refsect1 id="sql-dropcast-description"> |
| <title>Description</title> |
| |
| <para> |
| <command>DROP CAST</command> removes a previously defined cast. |
| </para> |
| |
| <para> |
| To be able to drop a cast, you must own the source or the target |
| data type. These are the same privileges that are required to |
| create a cast. |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Parameters</title> |
| |
| <variablelist> |
| |
| <varlistentry> |
| <term><literal>IF EXISTS</literal></term> |
| <listitem> |
| <para> |
| Do not throw an error if the cast does not exist. A notice is issued |
| in this case. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><replaceable>sourcetype</replaceable></term> |
| |
| <listitem> |
| <para> |
| The name of the source data type of the cast. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><replaceable>targettype</replaceable></term> |
| |
| <listitem> |
| <para> |
| The name of the target data type of the cast. |
| </para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><literal>CASCADE</literal></term> |
| <term><literal>RESTRICT</literal></term> |
| |
| <listitem> |
| <para> |
| These key words do not have any effect, since there are no |
| dependencies on casts. |
| </para> |
| </listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1 id="sql-dropcast-examples"> |
| <title>Examples</title> |
| |
| <para> |
| To drop the cast from type <type>text</type> to type <type>int</type>: |
| <programlisting> |
| DROP CAST (text AS int); |
| </programlisting> |
| </para> |
| </refsect1> |
| |
| <refsect1 id="sql-dropcast-compat"> |
| <title>Compatibility</title> |
| |
| <para> |
| The <command>DROP CAST</command> command conforms to the SQL standard. |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| |
| <simplelist type="inline"> |
| <member><xref linkend="sql-createcast" endterm="sql-createcast-title"></member> |
| </simplelist> |
| </refsect1> |
| |
| </refentry> |