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<h1 class="refname">db2_prepare</h1>
<p class="verinfo">(PECL ibm_db2 >= 1.0.0)</p><p class="refpurpose"><span class="refname">db2_prepare</span> — <span class="dc-title">
Prepares an SQL statement to be executed
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.db2-prepare-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">resource</span> <span class="methodname"><strong>db2_prepare</strong></span>
( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$connection</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$statement</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$options</code></span>
] )</div>
<p class="para rdfs-comment">
<span class="function"><strong>db2_prepare()</strong></span> creates a prepared SQL statement which can
include 0 or more parameter markers (<em>?</em> characters)
representing parameters for input, output, or input/output. You can pass
parameters to the prepared statement using
<span class="function"><a href="function.db2-bind-param.html" class="function">db2_bind_param()</a></span>, or for input values only, as an array
passed to <span class="function"><a href="function.db2-execute.html" class="function">db2_execute()</a></span>.
</p>
<p class="para">
There are three main advantages to using prepared statements in your
application:
<ul class="itemizedlist">
<li class="listitem">
<p class="para">
<em class="emphasis">Performance</em>: when you prepare a statement, the
database server creates an optimized access plan for retrieving data with
that statement. Subsequently issuing the prepared statement with
<span class="function"><a href="function.db2-execute.html" class="function">db2_execute()</a></span> enables the statements to reuse that
access plan and avoids the overhead of dynamically creating a new access
plan for every statement you issue.
</p>
</li>
<li class="listitem">
<p class="para">
<em class="emphasis">Security</em>: when you prepare a statement, you can
include parameter markers for input values. When you execute a prepared
statement with input values for placeholders, the database server checks
each input value to ensure that the type matches the column definition or
parameter definition.
</p>
</li>
<li class="listitem">
<p class="para">
<em class="emphasis">Advanced functionality</em>: Parameter markers not only
enable you to pass input values to prepared SQL statements, they also
enable you to retrieve OUT and INOUT parameters from stored procedures
using <span class="function"><a href="function.db2-bind-param.html" class="function">db2_bind_param()</a></span>.
</p>
</li>
</ul>
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.db2-prepare-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">connection</code></dt>
<dd>
<p class="para">
A valid database connection resource variable as returned from
<span class="function"><a href="function.db2-connect.html" class="function">db2_connect()</a></span> or <span class="function"><a href="function.db2-pconnect.html" class="function">db2_pconnect()</a></span>.
</p>
</dd>
<dt>
<code class="parameter">statement</code></dt>
<dd>
<p class="para">
An SQL statement, optionally containing one or more parameter markers..
</p>
</dd>
<dt>
<code class="parameter">options</code></dt>
<dd>
<p class="para">
An associative array containing statement options. You can use this
parameter to request a scrollable cursor on database servers that
support this functionality.
</p>
<p class="para">
For a description of valid statement options, see
<span class="function"><a href="function.db2-set-option.html" class="function">db2_set_option()</a></span>.
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.db2-prepare-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns a statement resource if the SQL statement was successfully parsed and
prepared by the database server. Returns <strong><code>FALSE</code></strong> if the database server
returned an error. You can determine which error was returned by calling
<span class="function"><a href="function.db2-stmt-error.html" class="function">db2_stmt_error()</a></span> or <span class="function"><a href="function.db2-stmt-errormsg.html" class="function">db2_stmt_errormsg()</a></span>.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.db2-prepare-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-1303">
<p><strong>Example #1 Preparing and executing an SQL statement with parameter markers</strong></p>
<div class="example-contents"><p>
The following example prepares an INSERT statement that accepts four
parameter markers, then iterates over an array of arrays containing the
input values to be passed to <span class="function"><a href="function.db2-execute.html" class="function">db2_execute()</a></span>.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$animals </span><span style="color: #007700">= array(<br /> array(</span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #DD0000">'cat'</span><span style="color: #007700">, </span><span style="color: #DD0000">'Pook'</span><span style="color: #007700">, </span><span style="color: #0000BB">3.2</span><span style="color: #007700">),<br /> array(</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #DD0000">'dog'</span><span style="color: #007700">, </span><span style="color: #DD0000">'Peaches'</span><span style="color: #007700">, </span><span style="color: #0000BB">12.3</span><span style="color: #007700">),<br /> array(</span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #DD0000">'horse'</span><span style="color: #007700">, </span><span style="color: #DD0000">'Smarty'</span><span style="color: #007700">, </span><span style="color: #0000BB">350.0</span><span style="color: #007700">),<br />);<br /><br /></span><span style="color: #0000BB">$insert </span><span style="color: #007700">= </span><span style="color: #DD0000">'INSERT INTO animals (id, breed, name, weight)<br /> VALUES (?, ?, ?, ?)'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$stmt </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_prepare</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #0000BB">$insert</span><span style="color: #007700">);<br />if (</span><span style="color: #0000BB">$stmt</span><span style="color: #007700">) {<br /> foreach (</span><span style="color: #0000BB">$animals </span><span style="color: #007700">as </span><span style="color: #0000BB">$animal</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$result </span><span style="color: #007700">= </span><span style="color: #0000BB">db2_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$stmt</span><span style="color: #007700">, </span><span style="color: #0000BB">$animal</span><span style="color: #007700">);<br /> }<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.db2-prepare-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.db2-bind-param.html" class="function" rel="rdfs-seeAlso">db2_bind_param()</a> - Binds a PHP variable to an SQL statement parameter</span></li>
<li class="member"><span class="function"><a href="function.db2-execute.html" class="function" rel="rdfs-seeAlso">db2_execute()</a> - Executes a prepared SQL statement</span></li>
<li class="member"><span class="function"><a href="function.db2-stmt-error.html" class="function" rel="rdfs-seeAlso">db2_stmt_error()</a> - Returns a string containing the SQLSTATE returned by an SQL statement</span></li>
<li class="member"><span class="function"><a href="function.db2-stmt-errormsg.html" class="function" rel="rdfs-seeAlso">db2_stmt_errormsg()</a> - Returns a string containing the last SQL statement error message</span></li>
</ul>
</p>
</div>
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