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118 lines
2.5 KiB
Plaintext
118 lines
2.5 KiB
Plaintext
<!--
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doc/src/sgml/ref/drop_cast.sgml
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PostgreSQL documentation
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-->
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<refentry id="sql-dropcast">
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<indexterm zone="sql-dropcast">
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<primary>DROP CAST</primary>
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</indexterm>
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<refmeta>
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<refentrytitle>DROP CAST</refentrytitle>
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<manvolnum>7</manvolnum>
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<refmiscinfo>SQL - Language Statements</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>DROP CAST</refname>
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<refpurpose>remove a cast</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<synopsis>
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DROP CAST [ IF EXISTS ] (<replaceable>source_type</replaceable> AS <replaceable>target_type</replaceable>) [ CASCADE | RESTRICT ]
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</synopsis>
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</refsynopsisdiv>
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<refsect1 id="sql-dropcast-description">
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<title>Description</title>
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<para>
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<command>DROP CAST</command> removes a previously defined cast.
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</para>
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<para>
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To be able to drop a cast, you must own the source or the target
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data type. These are the same privileges that are required to
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create a cast.
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</para>
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</refsect1>
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<refsect1>
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<title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><literal>IF EXISTS</literal></term>
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<listitem>
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<para>
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Do not throw an error if the cast does not exist. A notice is issued
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in this case.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable>source_type</replaceable></term>
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<listitem>
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<para>
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The name of the source data type of the cast.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable>target_type</replaceable></term>
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<listitem>
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<para>
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The name of the target data type of the cast.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>CASCADE</literal></term>
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<term><literal>RESTRICT</literal></term>
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<listitem>
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<para>
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These key words do not have any effect, since there are no
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dependencies on casts.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 id="sql-dropcast-examples">
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<title>Examples</title>
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<para>
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To drop the cast from type <type>text</type> to type <type>int</type>:
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<programlisting>
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DROP CAST (text AS int);
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</programlisting></para>
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</refsect1>
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<refsect1 id="sql-dropcast-compat">
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<title>Compatibility</title>
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<para>
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The <command>DROP CAST</command> command conforms to the SQL standard.
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</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<simplelist type="inline">
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<member><xref linkend="sql-createcast"/></member>
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</simplelist>
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</refsect1>
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</refentry>
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