diff options
Diffstat (limited to 'doc/src/sgml/html/spi-spi-cursor-open.html')
| -rw-r--r-- | doc/src/sgml/html/spi-spi-cursor-open.html | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/doc/src/sgml/html/spi-spi-cursor-open.html b/doc/src/sgml/html/spi-spi-cursor-open.html new file mode 100644 index 0000000..b474efa --- /dev/null +++ b/doc/src/sgml/html/spi-spi-cursor-open.html @@ -0,0 +1,47 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>SPI_cursor_open</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="spi-spi-execp.html" title="SPI_execp" /><link rel="next" href="spi-spi-cursor-open-with-args.html" title="SPI_cursor_open_with_args" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">SPI_cursor_open</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="spi-spi-execp.html" title="SPI_execp">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="spi-interface.html" title="47.1. Interface Functions">Up</a></td><th width="60%" align="center">47.1. Interface Functions</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="spi-spi-cursor-open-with-args.html" title="SPI_cursor_open_with_args">Next</a></td></tr></table><hr /></div><div class="refentry" id="SPI-SPI-CURSOR-OPEN"><div class="titlepage"></div><a id="id-1.8.12.8.19.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">SPI_cursor_open</span></h2><p>SPI_cursor_open — set up a cursor using a statement created with <code class="function">SPI_prepare</code></p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis"> +Portal SPI_cursor_open(const char * <em class="parameter"><code>name</code></em>, SPIPlanPtr <em class="parameter"><code>plan</code></em>, + Datum * <em class="parameter"><code>values</code></em>, const char * <em class="parameter"><code>nulls</code></em>, + bool <em class="parameter"><code>read_only</code></em>) +</pre></div><div class="refsect1" id="id-1.8.12.8.19.5"><h2>Description</h2><p> + <code class="function">SPI_cursor_open</code> sets up a cursor (internally, + a portal) that will execute a statement 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 statement 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 C function (it can, in fact, live + to the end of the current transaction). Returning the portal name + to the C function's caller provides a way of returning a row set as + result. + </p><p> + The passed-in parameter data will be copied into the cursor's portal, so it + can be freed while the cursor still exists. + </p></div><div class="refsect1" id="id-1.8.12.8.19.6"><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">const char * <em class="parameter"><code>name</code></em></code></span></dt><dd><p> + name for portal, or <code class="symbol">NULL</code> to let the system + select a name + </p></dd><dt><span class="term"><code class="literal">SPIPlanPtr <em class="parameter"><code>plan</code></em></code></span></dt><dd><p> + prepared statement (returned by <code class="function">SPI_prepare</code>) + </p></dd><dt><span class="term"><code class="literal">Datum * <em class="parameter"><code>values</code></em></code></span></dt><dd><p> + An array of actual parameter values. Must have same length as the + statement's number of arguments. + </p></dd><dt><span class="term"><code class="literal">const char * <em class="parameter"><code>nulls</code></em></code></span></dt><dd><p> + An array describing which parameters are null. Must have same length as + the statement's number of arguments. + </p><p> + If <em class="parameter"><code>nulls</code></em> is <code class="symbol">NULL</code> then + <code class="function">SPI_cursor_open</code> assumes that no parameters + are null. Otherwise, each entry of the <em class="parameter"><code>nulls</code></em> + array should be <code class="literal">' '</code> if the corresponding parameter + value is non-null, or <code class="literal">'n'</code> if the corresponding parameter + value is null. (In the latter case, the actual value in the + corresponding <em class="parameter"><code>values</code></em> entry doesn't matter.) Note + that <em class="parameter"><code>nulls</code></em> is not a text string, just an array: + it does not need a <code class="literal">'\0'</code> terminator. + </p></dd><dt><span class="term"><code class="literal">bool <em class="parameter"><code>read_only</code></em></code></span></dt><dd><p><code class="literal">true</code> for read-only execution</p></dd></dl></div></div><div class="refsect1" id="id-1.8.12.8.19.7"><h2>Return Value</h2><p> + Pointer to portal containing the cursor. Note there is no error + return convention; any error will be reported via <code class="function">elog</code>. + </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="spi-spi-execp.html" title="SPI_execp">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="spi-interface.html" title="47.1. Interface Functions">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="spi-spi-cursor-open-with-args.html" title="SPI_cursor_open_with_args">Next</a></td></tr><tr><td width="40%" align="left" valign="top">SPI_execp </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="40%" align="right" valign="top"> SPI_cursor_open_with_args</td></tr></table></div></body></html>
\ No newline at end of file |