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<title>SPI_cursor_open</title>
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en">
<a name="spi-spi-cursor-open"></a><div class="titlepage"></div>
<div class="refnamediv">
<h2>Name</h2>
<p>SPI_cursor_open — set up a cursor using a plan created with <code class="function">SPI_prepare</code></p>
</div>
<a name="id736609"></a><div class="refsynopsisdiv">
<h2>Synopsis</h2>
<pre class="synopsis">Portal SPI_cursor_open(const char * <em class="parameter"><code>name</code></em>, void * <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" lang="en">
<a name="id736656"></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" lang="en">
<a name="id736695"></a><h2>Arguments</h2>
<div class="variablelist"><dl>
<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">void * <em class="parameter"><code>plan</code></em></code></span></dt>
<dd><p> execution plan (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
plan'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 plan's number of arguments.
<code class="literal">n</code> indicates a null value (entry in
<em class="parameter"><code>values</code></em> will be ignored); a space indicates a
nonnull value (entry in <em class="parameter"><code>values</code></em> is valid).
</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.
</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" lang="en">
<a name="id736848"></a><h2>Return Value</h2>
<p> pointer to portal containing the cursor, or <code class="symbol">NULL</code>
on error
</p>
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