123 lines
3.4 KiB
Plaintext
123 lines
3.4 KiB
Plaintext
<!--
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doc/src/sgml/ref/create_access_method.sgml
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PostgreSQL documentation
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-->
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<refentry id="sql-create-access-method">
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<indexterm zone="sql-create-access-method">
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<primary>CREATE ACCESS METHOD</primary>
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</indexterm>
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<refmeta>
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<refentrytitle>CREATE ACCESS METHOD</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>CREATE ACCESS METHOD</refname>
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<refpurpose>define a new access method</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<synopsis>
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CREATE ACCESS METHOD <replaceable class="parameter">name</replaceable>
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TYPE <replaceable class="parameter">access_method_type</replaceable>
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HANDLER <replaceable class="parameter">handler_function</replaceable>
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</synopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>
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<command>CREATE ACCESS METHOD</command> creates a new access method.
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</para>
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<para>
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The access method name must be unique within the database.
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</para>
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<para>
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Only superusers can define new access methods.
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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><replaceable class="parameter">name</replaceable></term>
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<listitem>
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<para>
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The name of the access method to be created.
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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 class="parameter">access_method_type</replaceable></term>
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<listitem>
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<para>
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This clause specifies the type of access method to define.
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Only <literal>TABLE</literal> and <literal>INDEX</literal>
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are supported at present.
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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 class="parameter">handler_function</replaceable></term>
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<listitem>
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<para>
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<replaceable class="parameter">handler_function</replaceable> is the
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name (possibly schema-qualified) of a previously registered function
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that represents the access method. The handler function must be
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declared to take a single argument of type <type>internal</type>,
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and its return type depends on the type of access method;
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for <literal>TABLE</literal> access methods, it must
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be <type>table_am_handler</type> and for <literal>INDEX</literal>
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access methods, it must be <type>index_am_handler</type>.
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The C-level API that the handler function must implement varies
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depending on the type of access method. The table access method API
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is described in <xref linkend="tableam"/> and the index access method
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API is described in <xref linkend="indexam"/>.
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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>
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<title>Examples</title>
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<para>
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Create an index access method <literal>heptree</literal> with
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handler function <literal>heptree_handler</literal>:
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<programlisting>
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CREATE ACCESS METHOD heptree TYPE INDEX HANDLER heptree_handler;
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</programlisting></para>
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</refsect1>
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<refsect1>
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<title>Compatibility</title>
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<para>
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<command>CREATE ACCESS METHOD</command> is a
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<productname>PostgreSQL</productname> extension.
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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-drop-access-method"/></member>
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<member><xref linkend="sql-createopclass"/></member>
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<member><xref linkend="sql-createopfamily"/></member>
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</simplelist>
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</refsect1>
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</refentry>
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