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<title>Submits a request to create a prepared statement with the
given parameters, and waits for completion.</title>
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<h1 class="refname">pg_prepare</h1>
<p class="verinfo">(PHP 5 >= 5.1.0)</p><p class="refpurpose"><span class="refname">pg_prepare</span> — <span class="dc-title"> Submits a request to create a prepared statement with the
given parameters, and waits for completion.</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.pg-prepare-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">resource</span> <span class="methodname"><strong>pg_prepare</strong></span>
([ <span class="methodparam"><span class="type">resource</span> <code class="parameter">$connection</code></span>
], <span class="methodparam"><span class="type">string</span> <code class="parameter">$stmtname</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$query</code></span>
)</div>
<p class="para rdfs-comment">
<span class="function"><strong>pg_prepare()</strong></span> creates a prepared statement for later execution with
<span class="function"><a href="function.pg-execute.html" class="function">pg_execute()</a></span> or <span class="function"><a href="function.pg-send-execute.html" class="function">pg_send_execute()</a></span>.
This feature allows commands that will be used repeatedly to
be parsed and planned just once, rather than each time they are executed.
<span class="function"><strong>pg_prepare()</strong></span> is supported only against PostgreSQL 7.4 or
higher connections; it will fail when using earlier versions.
</p>
<p class="para">
The function creates a prepared statement named <em><code class="parameter">stmtname</code></em> from the <em><code class="parameter">query</code></em>
string, which must contain a single SQL command. <em><code class="parameter">stmtname</code></em> may be "" to
create an unnamed statement, in which case any pre-existing unnamed
statement is automatically replaced; otherwise it is an error if the
statement name is already defined in the current session. If any parameters
are used, they are referred to in the <em><code class="parameter">query</code></em> as $1, $2, etc.
</p>
<p class="para">
Prepared statements for use with <span class="function"><strong>pg_prepare()</strong></span> can also be created by
executing SQL <em>PREPARE</em> statements. (But <span class="function"><strong>pg_prepare()</strong></span> is more flexible since it
does not require parameter types to be pre-specified.) Also, although there
is no PHP function for deleting a prepared statement, the SQL <em>DEALLOCATE</em>
statement can be used for that purpose.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.pg-prepare-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">connection</code></em></span>
<dd>
<p class="para">
PostgreSQL database connection resource. When
<em><code class="parameter">connection</code></em> is not present, the default connection
is used. The default connection is the last connection made by
<span class="function"><a href="function.pg-connect.html" class="function">pg_connect()</a></span> or <span class="function"><a href="function.pg-pconnect.html" class="function">pg_pconnect()</a></span>.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">stmtname</code></em></span>
<dd>
<p class="para">
The name to give the prepared statement. Must be unique per-connection. If
"" is specified, then an unnamed statement is created, overwriting any
previously defined unnamed statement.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">query</code></em></span>
<dd>
<p class="para">
The parameterized SQL statement. Must contain only a single statement.
(multiple statements separated by semi-colons are not allowed.) If any parameters
are used, they are referred to as $1, $2, etc.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.pg-prepare-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
A query result resource on success or <strong><code>FALSE</code></strong> on failure.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.pg-prepare-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-2107">
<p><strong>Example #1 Using <span class="function"><strong>pg_prepare()</strong></span></strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Connect to a database named "mary"<br /></span><span style="color: #0000BB">$dbconn </span><span style="color: #007700">= </span><span style="color: #0000BB">pg_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"dbname=mary"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Prepare a query for execution<br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">pg_prepare</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbconn</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_query"</span><span style="color: #007700">, </span><span style="color: #DD0000">'SELECT * FROM shops WHERE name = $1'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Execute the prepared query. Note that it is not necessary to escape<br />// the string "Joe's Widgets" in any way<br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">pg_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbconn</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_query"</span><span style="color: #007700">, array(</span><span style="color: #DD0000">"Joe's Widgets"</span><span style="color: #007700">));<br /><br /></span><span style="color: #FF8000">// Execute the same prepared query, this time with a different parameter<br /></span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">pg_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbconn</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_query"</span><span style="color: #007700">, array(</span><span style="color: #DD0000">"Clothes Clothes Clothes"</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.pg-prepare-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.pg-execute.html" class="function" rel="rdfs-seeAlso">pg_execute()</a> - Sends a request to execute a prepared statement with given parameters, and waits for the result.</span></li>
<li class="member"> <span class="function"><a href="function.pg-send-execute.html" class="function" rel="rdfs-seeAlso">pg_send_execute()</a> - Sends a request to execute a prepared statement with given parameters, without waiting for the result(s).</span></li>
</ul>
</p>
</div>
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