<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >CREATE ACCESS METHOD</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 9.6.17 Documentation" HREF="index.html"><LINK REL="UP" TITLE="SQL Commands" HREF="sql-commands.html"><LINK REL="PREVIOUS" TITLE="COPY" HREF="sql-copy.html"><LINK REL="NEXT" TITLE="CREATE AGGREGATE" HREF="sql-createaggregate.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2020-02-15T12:30:38"></HEAD ><BODY CLASS="REFENTRY" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="4" ALIGN="center" VALIGN="bottom" ><A HREF="index.html" >PostgreSQL 9.6.17 Documentation</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A TITLE="COPY" HREF="sql-copy.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="CREATE AGGREGATE" HREF="sql-createaggregate.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SQL-CREATE-ACCESS-METHOD" ></A >CREATE ACCESS METHOD</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN78531" ></A ><H2 >Name</H2 >CREATE ACCESS METHOD -- define a new access method</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN78534" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >CREATE ACCESS METHOD <TT CLASS="REPLACEABLE" ><I >name</I ></TT > TYPE <TT CLASS="REPLACEABLE" ><I >access_method_type</I ></TT > HANDLER <TT CLASS="REPLACEABLE" ><I >handler_function</I ></TT ></PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN78539" ></A ><H2 >Description</H2 ><P > <TT CLASS="COMMAND" >CREATE ACCESS METHOD</TT > creates a new access method. </P ><P > The access method name must be unique within the database. </P ><P > Only superusers can define new access methods. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN78545" ></A ><H2 >Parameters</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="REPLACEABLE" ><I >name</I ></TT ></DT ><DD ><P > The name of the access method to be created. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >access_method_type</I ></TT ></DT ><DD ><P > This clause specifies the type of access method to define. Only <TT CLASS="LITERAL" >INDEX</TT > is supported at present. </P ></DD ><DT ><TT CLASS="REPLACEABLE" ><I >handler_function</I ></TT ></DT ><DD ><P > <TT CLASS="REPLACEABLE" ><I >handler_function</I ></TT > is the name (possibly schema-qualified) of a previously registered function that represents the access method. The handler function must be declared to take a single argument of type <TT CLASS="TYPE" >internal</TT >, and its return type depends on the type of access method; for <TT CLASS="LITERAL" >INDEX</TT > access methods, it must be <TT CLASS="TYPE" >index_am_handler</TT >. The C-level API that the handler function must implement varies depending on the type of access method. The index access method API is described in <A HREF="indexam.html" >Chapter 59</A >. </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN78569" ></A ><H2 >Examples</H2 ><P > Create an index access method <TT CLASS="LITERAL" >heptree</TT > with handler function <TT CLASS="LITERAL" >heptree_handler</TT >: </P><PRE CLASS="PROGRAMLISTING" >CREATE ACCESS METHOD heptree TYPE INDEX HANDLER heptree_handler;</PRE ><P> </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN78575" ></A ><H2 >Compatibility</H2 ><P > <TT CLASS="COMMAND" >CREATE ACCESS METHOD</TT > is a <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > extension. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN78580" ></A ><H2 >See Also</H2 ><A HREF="sql-drop-access-method.html" >DROP ACCESS METHOD</A >, <A HREF="sql-createopclass.html" >CREATE OPERATOR CLASS</A >, <A HREF="sql-createopfamily.html" >CREATE OPERATOR FAMILY</A ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sql-copy.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sql-createaggregate.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >COPY</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="sql-commands.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >CREATE AGGREGATE</TD ></TR ></TABLE ></DIV ></BODY ></HTML >