<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >SPI_cursor_open</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 8.0.11 Documentation" HREF="index.html"><LINK REL="UP" TITLE="Interface Functions" HREF="spi.html#SPI-INTERFACE"><LINK REL="PREVIOUS" TITLE="SPI_execp" HREF="spi-spi-execp.html"><LINK REL="NEXT" TITLE="SPI_cursor_find" HREF="spi-spi-cursor-find.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="2007-02-02T03:57:22"></HEAD ><BODY CLASS="REFENTRY" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" >PostgreSQL 8.0.11 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="spi-spi-execp.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="spi-spi-execp.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="spi-spi-cursor-find.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="spi-spi-cursor-find.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SPI-SPI-CURSOR-OPEN" ></A >SPI_cursor_open</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN35251" ></A ><H2 >Name</H2 >SPI_cursor_open -- set up a cursor using a plan created with <CODE CLASS="FUNCTION" >SPI_prepare</CODE ></DIV ><A NAME="AEN35255" ></A ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN35257" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >Portal SPI_cursor_open(const char * <TT CLASS="PARAMETER" >name</TT >, void * <TT CLASS="PARAMETER" >plan</TT >, Datum * <TT CLASS="PARAMETER" >values</TT >, const char * <TT CLASS="PARAMETER" >nulls</TT >, bool <TT CLASS="PARAMETER" >read_only</TT >)</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN35264" ></A ><H2 >Description</H2 ><P > <CODE CLASS="FUNCTION" >SPI_cursor_open</CODE > sets up a cursor (internally, a portal) that will execute a plan prepared by <CODE CLASS="FUNCTION" >SPI_prepare</CODE >. The parameters have the same meanings as the corresponding parameters to <CODE CLASS="FUNCTION" >SPI_execute_plan</CODE >. </P ><P > Using a cursor instead of executing the plan directly has two benefits. First, the result rows can be retrieved a few at a time, avoiding memory overrun for queries that return many rows. Second, a portal can outlive the current procedure (it can, in fact, live to the end of the current transaction). Returning the portal name to the procedure's caller provides a way of returning a row set as result. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN35271" ></A ><H2 >Arguments</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="LITERAL" >const char * <TT CLASS="PARAMETER" >name</TT ></TT ></DT ><DD ><P > name for portal, or <TT CLASS="SYMBOL" >NULL</TT > to let the system select a name </P ></DD ><DT ><TT CLASS="LITERAL" >void * <TT CLASS="PARAMETER" >plan</TT ></TT ></DT ><DD ><P > execution plan (returned by <CODE CLASS="FUNCTION" >SPI_prepare</CODE >) </P ></DD ><DT ><TT CLASS="LITERAL" >Datum * <TT CLASS="PARAMETER" >values</TT ></TT ></DT ><DD ><P > An array of actual parameter values. Must have same length as the plan's number of arguments. </P ></DD ><DT ><TT CLASS="LITERAL" >const char * <TT CLASS="PARAMETER" >nulls</TT ></TT ></DT ><DD ><P > An array describing which parameters are null. Must have same length as the plan's number of arguments. <TT CLASS="LITERAL" >n</TT > indicates a null value (entry in <TT CLASS="PARAMETER" >values</TT > will be ignored); a space indicates a nonnull value (entry in <TT CLASS="PARAMETER" >values</TT > is valid). </P ><P > If <TT CLASS="PARAMETER" >nulls</TT > is <TT CLASS="SYMBOL" >NULL</TT > then <CODE CLASS="FUNCTION" >SPI_cursor_open</CODE > assumes that no parameters are null. </P ></DD ><DT ><TT CLASS="LITERAL" >bool <TT CLASS="PARAMETER" >read_only</TT ></TT ></DT ><DD ><P > <TT CLASS="LITERAL" >true</TT > for read-only execution </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN35314" ></A ><H2 >Return Value</H2 ><P > pointer to portal containing the cursor, or <TT CLASS="SYMBOL" >NULL</TT > on error </P ></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="spi-spi-execp.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="spi-spi-cursor-find.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SPI_execp</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="spi.html#SPI-INTERFACE" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SPI_cursor_find</TD ></TR ></TABLE ></DIV ></BODY ></HTML >