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<title>Converts keys specifying an index to its identifying string</title>
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<h1 class="refname">MongoCollection::toIndexString</h1>
<p class="verinfo">(PECL mongo >=0.9.0)</p><p class="refpurpose"><span class="refname">MongoCollection::toIndexString</span> — <span class="dc-title">Converts keys specifying an index to its identifying string</span></p>
</div>
<div class="refsect1 description" id="refsect1-mongocollection.toindexstring-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="modifier">static protected</span> <span class="type">string</span> <span class="methodname"><strong>MongoCollection::toIndexString</strong></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$keys</code></span>
)</div>
<div class="warning"><strong class="warning">Warning</strong>
<p class="para">
This method is deprecated since version 1.5.0.
</p>
</div>
</div>
<div class="refsect1 parameters" id="refsect1-mongocollection.toindexstring-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">keys</code>
</dt>
<dd>
<p class="para">
Field or fields to convert to the identifying string
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-mongocollection.toindexstring-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns a string that describes the index.
</p>
</div>
<div class="refsect1 examples" id="refsect1-mongocollection.toindexstring-examples">
<h3 class="title">Examples</h3>
<div class="example" id="example-1608">
<p><strong>Example #1 <span class="function"><strong>MongoCollection::toIndexString()</strong></span> example</strong></p>
<div class="example-contents"><p>This example shows how you can create an index name out of keys.
Because this is a protected (static) method, you need to overload it in a
child class first.</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Create inherited class to make the method "public".<br /></span><span style="color: #007700">class </span><span style="color: #0000BB">MyCollection </span><span style="color: #007700">extends </span><span style="color: #0000BB">MongoCollection<br /></span><span style="color: #007700">{<br /> static public function </span><span style="color: #0000BB">toIndexString</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">)<br /> {<br /> return </span><span style="color: #0000BB">parent</span><span style="color: #007700">::</span><span style="color: #0000BB">toIndexString</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">);<br /> }<br />}<br /><br />echo </span><span style="color: #0000BB">MyCollection</span><span style="color: #007700">::</span><span style="color: #0000BB">toIndexString</span><span style="color: #007700">(</span><span style="color: #DD0000">"foo"</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #FF8000">// Outputs: foo_1<br /><br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">MyCollection</span><span style="color: #007700">::</span><span style="color: #0000BB">toIndexString</span><span style="color: #007700">(array(</span><span style="color: #DD0000">'name' </span><span style="color: #007700">=> </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #DD0000">'age' </span><span style="color: #007700">=> -</span><span style="color: #0000BB">1</span><span style="color: #007700">)), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #FF8000">// Outputs: name_1_age_-1<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</div>
<div class="refsect1 seealso" id="refsect1-mongocollection.toindexstring-seealso">
<h3 class="title">See Also</h3>
<p class="para">
MongoDB core docs on <a href="https://docs.mongodb.com/manual/indexes/" class="link external">» indexes</a>.
</p>
</div>
<div class="refsect1 changelog" id="refsect1-mongocollection.toindexstring-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>1.5.0</td>
<td>
This method has been deprecated.
</td>
</tr>
</tbody>
</table>
</p>
</div>
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