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<title>The MongoCommandCursor class</title>
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<h1 class="title">The MongoCommandCursor class</h1>
<div class="partintro"><p class="verinfo">(PECL mongo >=1.5.0)</p>
<div class="section" id="mongocommandcursor.intro">
<h2 class="title">Introduction</h2>
<p class="para">
A command cursor is similar to a <a href="class.mongocursor.html" class="classname">MongoCursor</a> except
that you use it for iterating through the results of a database command
instead of a normal query. Command cursors are useful for iterating over
large result sets that might exceed the document size limit (currently 16MB)
of a single <span class="function"><a href="mongodb.command.html" class="function">MongoDB::command()</a></span> response.
</p>
<p class="para">
While you can create command cursors using
<span class="function"><a href="mongocommandcursor.construct.html" class="function">MongoCommandCursor::__construct()</a></span> or the
<span class="function"><a href="mongocommandcursor.createfromdocument.html" class="function">MongoCommandCursor::createFromDocument()</a></span> factory method,
you will generally want to use command-specific helpers such as
<span class="function"><a href="mongocollection.aggregatecursor.html" class="function">MongoCollection::aggregateCursor()</a></span>.
</p>
<p class="para">
Note that the cursor does not "contain" the database command's results; it
just manages iteration through them. Thus, if you print a cursor (f.e. with
<span class="function"><a href="function.var-dump.html" class="function">var_dump()</a></span> or <span class="function"><a href="function.print-r.html" class="function">print_r()</a></span>), you will see
the cursor object but not the result documents.
</p>
</div>
<div class="section">
<h2 class="title">Cursor Stages</h2>
<p class="para">
A <strong class="classname">MongoCommandCursor</strong> has two "life stages": pre-
and post- command. When a cursor is created, it has not yet contacted the
database, so it is in its pre-command state. When the client first attempts
to get a result (by calling <span class="function"><a href="mongocommandcursor.rewind.html" class="function">MongoCommandCursor::rewind()</a></span>,
directly or indirectly), the cursor moves into the post-command state.
</p>
<p class="para">
The command cursor's batch size and socket timeout may be configured in both
the pre- and post- command states.
</p>
<p class="para">
<div class="example" id="example-1632">
<p><strong>Example #1 Adding options to <strong class="classname">MongoCommandCursor</strong></strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$cursor </span><span style="color: #007700">= new </span><span style="color: #0000BB">MongoCommandCursor</span><span style="color: #007700">(...);<br /><br /></span><span style="color: #0000BB">$cursor </span><span style="color: #007700">= </span><span style="color: #0000BB">$cursor</span><span style="color: #007700">-></span><span style="color: #0000BB">batchSize</span><span style="color: #007700">( </span><span style="color: #0000BB">4 </span><span style="color: #007700">);<br /><br />foreach (</span><span style="color: #0000BB">$cursor </span><span style="color: #007700">as </span><span style="color: #0000BB">$result</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="section" id="mongocommandcursor.synopsis">
<h2 class="title">Class synopsis</h2>
<div class="classsynopsis">
<div class="ooclass"></div>
<div class="classsynopsisinfo">
<span class="ooclass">
<strong class="classname">MongoCommandCursor</strong>
</span>
<span class="oointerface">implements
<span class="interfacename"><a href="class.mongocursorinterface.html" class="interfacename">MongoCursorInterface</a></span>
</span>
<span class="oointerface">,
<span class="interfacename"><a href="class.iterator.html" class="interfacename">Iterator</a></span>
</span>
{</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Methods */</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">MongoCommandCursor</span> <span class="methodname"><a href="mongocommandcursor.batchsize.html" class="methodname">batchSize</a></span>
( <span class="methodparam"><span class="type">int</span> <code class="parameter">$batchSize</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="methodname"><a href="mongocommandcursor.construct.html" class="methodname">__construct</a></span>
( <span class="methodparam"><span class="type"><a href="class.mongoclient.html" class="type MongoClient">MongoClient</a></span> <code class="parameter">$connection</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$ns</code></span>
, <span class="methodparam"><span class="type">array</span> <code class="parameter">$command</code><span class="initializer"> = array()</span></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="modifier">static</span> <span class="type">MongoCommandCursor</span> <span class="methodname"><a href="mongocommandcursor.createfromdocument.html" class="methodname">createFromDocument</a></span>
( <span class="methodparam"><span class="type"><a href="class.mongoclient.html" class="type MongoClient">MongoClient</a></span> <code class="parameter">$connection</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$hash</code></span>
, <span class="methodparam"><span class="type">array</span> <code class="parameter">$document</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><a href="mongocommandcursor.current.html" class="methodname">current</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="mongocommandcursor.dead.html" class="methodname">dead</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><a href="mongocommandcursor.getreadpreference.html" class="methodname">getReadPreference</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><a href="mongocommandcursor.info.html" class="methodname">info</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">int</span> <span class="methodname"><a href="mongocommandcursor.key.html" class="methodname">key</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">void</span> <span class="methodname"><a href="mongocommandcursor.next.html" class="methodname">next</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><a href="mongocommandcursor.rewind.html" class="methodname">rewind</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">MongoCommandCursor</span> <span class="methodname"><a href="mongocommandcursor.setreadpreference.html" class="methodname">setReadPreference</a></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">$tags</code></span>
] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">MongoCommandCursor</span> <span class="methodname"><a href="mongocommandcursor.timeout.html" class="methodname">timeout</a></span>
( <span class="methodparam"><span class="type">int</span> <code class="parameter">$ms</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><a href="mongocommandcursor.valid.html" class="methodname">valid</a></span>
( <span class="methodparam">void</span>
)</div>
}</div>
</div>
<div class="section">
<h2 class="title">See Also</h2>
<ul class="simplelist">
<li class="member"><span class="methodname"><a href="mongodb.command.html" class="methodname">MongoDB::command()</a></span></li>
<li class="member"><span class="methodname"><a href="mongocollection.aggregatecursor.html" class="methodname">MongoCollection::aggregateCursor()</a></span></li>
</ul>
</div>
</div>
<h2>Table of Contents</h2><ul class="chunklist chunklist_reference"><li><a href="mongocommandcursor.batchsize.html">MongoCommandCursor::batchSize</a> — Limits the number of elements returned in one batch</li><li><a href="mongocommandcursor.construct.html">MongoCommandCursor::__construct</a> — Create a new command cursor</li><li><a href="mongocommandcursor.createfromdocument.html">MongoCommandCursor::createFromDocument</a> — Create a new command cursor from an existing command response document</li><li><a href="mongocommandcursor.current.html">MongoCommandCursor::current</a> — Returns the current element</li><li><a href="mongocommandcursor.dead.html">MongoCommandCursor::dead</a> — Checks if there are results that have not yet been sent from the database</li><li><a href="mongocommandcursor.getreadpreference.html">MongoCommandCursor::getReadPreference</a> — Get the read preference for this command</li><li><a href="mongocommandcursor.info.html">MongoCommandCursor::info</a> — Gets information about the cursor's creation and iteration</li><li><a href="mongocommandcursor.key.html">MongoCommandCursor::key</a> — Returns the current result's index within the result set</li><li><a href="mongocommandcursor.next.html">MongoCommandCursor::next</a> — Advances the cursor to the next result</li><li><a href="mongocommandcursor.rewind.html">MongoCommandCursor::rewind</a> — Executes the command and resets the cursor to the start of the result set</li><li><a href="mongocommandcursor.setreadpreference.html">MongoCommandCursor::setReadPreference</a> — Set the read preference for this command</li><li><a href="mongocommandcursor.timeout.html">MongoCommandCursor::timeout</a> — Sets a client-side timeout for this command</li><li><a href="mongocommandcursor.valid.html">MongoCommandCursor::valid</a> — Checks if the cursor is reading a valid result</li></ul>
</div>
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