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<h1 class="refname">MongoCollection::setReadPreference</h1>
<p class="verinfo">(PECL mongo >=1.3.0)</p><p class="refpurpose"><span class="refname">MongoCollection::setReadPreference</span> — <span class="dc-title">Set the read preference for this collection</span></p>
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<div class="refsect1 description" id="refsect1-mongocollection.setreadpreference-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><strong>MongoCollection::setReadPreference</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$read_preference</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$tags</code></span>
] )</div>
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<div class="refsect1 parameters" id="refsect1-mongocollection.setreadpreference-parameters">
<h3 class="title">Parameters</h3>
<dl>
<dt>
<span class="term"><em><code class="parameter">read_preference</code></em></span><dd>
<p class="para">The read preference mode: <strong><code>MongoClient::RP_PRIMARY</code></strong>, <strong><code>MongoClient::RP_PRIMARY_PREFERRED</code></strong>, <strong><code>MongoClient::RP_SECONDARY</code></strong>, <strong><code>MongoClient::RP_SECONDARY_PREFERRED</code></strong>, or <strong><code>MongoClient::RP_NEAREST</code></strong>.</p></dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">tags</code></em></span><dd>
<p class="para">An array of zero or more tag sets, where each tag set is itself an array of criteria used to match tags on replica set members.</p></dd>
</dt>
</dl>
</div>
<div class="refsect1 returnvalues" id="refsect1-mongocollection.setreadpreference-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">Returns <strong><code>TRUE</code></strong> on success, or <strong><code>FALSE</code></strong> otherwise.</p>
</div>
<div class="refsect1 errors" id="refsect1-mongocollection.setreadpreference-errors">
<h3 class="title">Errors/Exceptions</h3>
<p class="para">Emits <strong><code>E_WARNING</code></strong> if either parameter is invalid, or if one or more tag sets are provided with the <strong><code>MongoClient::RP_PRIMARY</code></strong> read preference mode.</p>
</div>
<div class="refsect1 examples" id="refsect1-mongocollection.setreadpreference-examples">
<h3 class="title">Examples</h3>
<div class="example" id="example-1466">
<p><strong>Example #1 <span class="methodname"><strong>MongoCollection::setReadPreference()</strong></span> tag set array syntax example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$m </span><span style="color: #007700">= new </span><span style="color: #0000BB">MongoClient</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$c </span><span style="color: #007700">= </span><span style="color: #0000BB">$m</span><span style="color: #007700">-></span><span style="color: #0000BB">test</span><span style="color: #007700">-></span><span style="color: #0000BB">users</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// Prefer the nearest server in the "east" data center also used for reporting,<br />// but fall back to a server in the "west" data center<br /></span><span style="color: #0000BB">$c</span><span style="color: #007700">-></span><span style="color: #0000BB">setReadPreference</span><span style="color: #007700">(</span><span style="color: #0000BB">MongoClient</span><span style="color: #007700">::</span><span style="color: #0000BB">RP_NEAREST</span><span style="color: #007700">, array(<br /> array(</span><span style="color: #DD0000">'dc' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'east'</span><span style="color: #007700">, </span><span style="color: #DD0000">'use' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'reporting'</span><span style="color: #007700">),<br /> array(</span><span style="color: #DD0000">'dc' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'west'</span><span style="color: #007700">),<br />));<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
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</div>
</div>
<div class="refsect1 seealso" id="refsect1-mongocollection.setreadpreference-seealso">
<h3 class="title">See Also</h3>
<ul class="simplelist">
<li class="member">The <a href="mongo.readpreferences.html" class="link">read preferences</a> documentation.</li>
</ul>
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