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<h1 class="refname">MongoDB::execute</h1>
<p class="verinfo">(PECL mongo >=0.9.3)</p><p class="refpurpose"><span class="refname">MongoDB::execute</span> — <span class="dc-title">Runs JavaScript code on the database server.</span></p>
</div>
<div class="refsect1 description" id="refsect1-mongodb.execute-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><strong>MongoDB::execute</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">$code</code></span>
[, <span class="methodparam"><span class="type">array</span> <code class="parameter">$args</code><span class="initializer"> = array()</span></span>
] )</div>
<p class="para rdfs-comment">
The Mongo database server runs a JavaScript engine. This method allows you
to run arbitary JavaScript on the database. This can be useful if you want
touch a number of collections lightly, or process some results on the
database side to reduce the amount that has to be sent to the client.
</p>
<p class="para">
Running JavaScript in the database takes a write lock, meaning it blocks
other operations. Make sure you consider this before running a long script.
</p>
<p class="para">
This is a wrapper for a database command. This method is basically:
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /></span><span style="color: #007700">public function </span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$code</span><span style="color: #007700">, </span><span style="color: #0000BB">$args</span><span style="color: #007700">) {<br /> return </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">command</span><span style="color: #007700">(array(</span><span style="color: #DD0000">'$eval' </span><span style="color: #007700">=> </span><span style="color: #0000BB">$code</span><span style="color: #007700">, </span><span style="color: #DD0000">'args' </span><span style="color: #007700">=> </span><span style="color: #0000BB">$args</span><span style="color: #007700">));<br />}<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</p>
<p class="para">
MongoDB implies a return statement if you have a single statement on a single
line. This can cause some unintuitive behavior. For example, this returns
"foo":
</p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$db</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #DD0000">'"foo";'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">
However, these return <strong><code>NULL</code></strong>:
</p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$db</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #DD0000">'"bar"; "foo";'</span><span style="color: #007700">); </span><span style="color: #FF8000">// more than one statement<br /><br /></span><span style="color: #0000BB">$db</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #DD0000">'db.foo.count(<br />);'</span><span style="color: #007700">); </span><span style="color: #FF8000">// more than one line<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">
To avoid surprising behavior, it is best not to depend on MongoDB to decide
what to return, but to explicitly state a return value. In the examples
above, we can change them to:
</p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$db</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #DD0000">'"bar"; return "foo";'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$db</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #DD0000">'return db.foo.count(<br />);'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<p class="para">
Now the first statement will return "foo" and the second statement will
return a count of the "foo" collection.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-mongodb.execute-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term">
<em><code class="parameter">code</code></em>
</span>
<dd>
<p class="para">
<a href="class.mongocode.html" class="classname">MongoCode</a> or string to execute.
</p>
</dd>
</dt>
<dt>
<span class="term">
<em><code class="parameter">args</code></em>
</span>
<dd>
<p class="para">
Arguments to be passed to <em>code</em>.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-mongodb.execute-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the result of the evaluation.
</p>
</div>
<div class="refsect1 examples" id="refsect1-mongodb.execute-examples">
<h3 class="title">Examples</h3>
<div class="example" id="example-1419">
<p><strong>Example #1 Simple <span class="function"><strong>MongoDB::execute()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$response </span><span style="color: #007700">= </span><span style="color: #0000BB">$db</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #DD0000">"function() { return 'Hello, world!'; }"</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">$response</span><span style="color: #007700">[</span><span style="color: #DD0000">'retval'</span><span style="color: #007700">];<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output
something similar to:</p></div>
<div class="example-contents screen"><br />
Hello, world!<br />
</div>
</div>
<div class="example" id="example-1420">
<p><strong>Example #2 Parameter <span class="function"><strong>MongoDB::execute()</strong></span> example</strong></p>
<div class="example-contents"><p>
The optional array of parameters will be passed to the JavaScript function.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$response </span><span style="color: #007700">= </span><span style="color: #0000BB">$db</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #DD0000">"function(greeting, name) { return greeting+', '+name+'!'; }"</span><span style="color: #007700">, array(</span><span style="color: #DD0000">"Good bye"</span><span style="color: #007700">, </span><span style="color: #DD0000">"Joe"</span><span style="color: #007700">));<br />echo </span><span style="color: #0000BB">$response</span><span style="color: #007700">[</span><span style="color: #DD0000">'retval'</span><span style="color: #007700">];<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output
something similar to:</p></div>
<div class="example-contents screen"><br />
Good bye, Joe!<br />
</div>
</div>
<div class="example" id="example-1421">
<p><strong>Example #3 Scope example</strong></p>
<div class="example-contents"><p>
If a <a href="class.mongocode.html" class="classname">MongoCode</a> object is used instead of a string for
the first parameter, a scope can be passed in which the JavaScript will be
executed.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$func </span><span style="color: #007700">= <br /> </span><span style="color: #DD0000">"function(greeting, name) { "</span><span style="color: #007700">.<br /> </span><span style="color: #DD0000">"return greeting+', '+name+', says '+greeter;"</span><span style="color: #007700">.<br /> </span><span style="color: #DD0000">"}"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$scope </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"greeter" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"Fred"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$code </span><span style="color: #007700">= new </span><span style="color: #0000BB">MongoCode</span><span style="color: #007700">(</span><span style="color: #0000BB">$func</span><span style="color: #007700">, </span><span style="color: #0000BB">$scope</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$response </span><span style="color: #007700">= </span><span style="color: #0000BB">$db</span><span style="color: #007700">-></span><span style="color: #0000BB">execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$code</span><span style="color: #007700">, array(</span><span style="color: #DD0000">"Goodbye"</span><span style="color: #007700">, </span><span style="color: #DD0000">"Joe"</span><span style="color: #007700">));<br />echo </span><span style="color: #0000BB">$response</span><span style="color: #007700">[</span><span style="color: #DD0000">'retval'</span><span style="color: #007700">];<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output
something similar to:</p></div>
<div class="example-contents screen"><br />
Goodbye, Joe, says Fred <br />
</div>
</div>
</div>
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