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<title>The MongoId class</title>
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<h1 class="title">The MongoId class</h1>
<div class="partintro"><p class="verinfo">(PECL mongo >=0.8.0)</p>
<div class="warning"><strong class="warning">Warning</strong>
<p class="para">This extension that defines this class
is deprecated. Instead, the <a href="set.mongodb.html" class="link">MongoDB</a> extension should be used.
Alternatives to this class include:</p>
<ul class="simplelist">
<li class="member"><a href="class.mongodb-bson-objectid.html" class="classname">MongoDB\BSON\ObjectId</a></li>
</ul>
</div>
<div class="section" id="mongoid.intro">
<h2 class="title">Introduction</h2>
<p class="para">
A unique identifier created for database objects. If an object is inserted
into the database without an _id field, an _id field will be added to it
with a <strong class="classname">MongoId</strong> instance as its value. If the data
has a naturally occuring unique field (e.g. username or timestamp) it is
fine to use this as the _id field instead, and it will not be replaced with
a <strong class="classname">MongoId</strong>.
</p>
<p class="para">
Instances of the <strong class="classname">MongoId</strong> class fulfill the role that
autoincrementing does in a relational database: to provide a unique key if
the data does not naturally have one. Autoincrementing does not work well
with a sharded database, as it is difficult to determine the next number in
the sequence. This class fulfills the constraints of quickly generating a
value that is unique across shards.
</p>
<p class="para">
Each MongoId is 12 bytes (making its string form 24 hexadecimal characters).
The first four bytes are a timestamp, the next three are a hash of the
client machine's hostname, the next two are the two least significant bytes
of the process id running the script, and the last three bytes are an
incrementing value.
</p>
<p class="para">
<strong class="classname">MongoId</strong>s are serializable/unserializable. Their
serialized form is similar to their string form:
<div class="example-contents screen">
<div class="cdata"><pre>
C:7:"MongoId":24:{4af9f23d8ead0e1d32000000}
</pre></div>
</div>
</p>
</div>
<div class="section" id="mongoid.synopsis">
<h2 class="title">Class synopsis</h2>
<div class="classsynopsis">
<div class="ooclass"></div>
<div class="classsynopsisinfo">
<span class="ooclass">
<strong class="classname">MongoId</strong>
</span>
{</div>
<div class="fieldsynopsis">
<span class="modifier">public</span>
<span class="type">string</span>
<var class="varname"><a href="class.mongoid.html#mongoid.props.id">$<var class="varname">$id</var></a></var>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
;</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Methods */</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="methodname"><a href="mongoid.construct.html" class="methodname">__construct</a></span>
([ <span class="methodparam"><span class="type"><span class="type string|MongoId">string|MongoId</span></span> <code class="parameter">$id</code><span class="initializer"> = <strong><code>NULL</code></strong></span></span>
] )</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="modifier">static</span> <span class="type">string</span> <span class="methodname"><a href="mongoid.gethostname.html" class="methodname">getHostname</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">int</span> <span class="methodname"><a href="mongoid.getinc.html" class="methodname">getInc</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">int</span> <span class="methodname"><a href="mongoid.getpid.html" class="methodname">getPID</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">int</span> <span class="methodname"><a href="mongoid.gettimestamp.html" class="methodname">getTimestamp</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="modifier">static</span> <span class="type">bool</span> <span class="methodname"><a href="mongoid.isvalid.html" class="methodname">isValid</a></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$value</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="modifier">static</span> <span class="type">MongoId</span> <span class="methodname"><a href="mongoid.set-state.html" class="methodname">__set_state</a></span>
( <span class="methodparam"><span class="type">array</span> <code class="parameter">$props</code></span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">string</span> <span class="methodname"><a href="mongoid.tostring.html" class="methodname">__toString</a></span>
( <span class="methodparam">void</span>
)</div>
}</div>
</div>
<div class="section">
<h2 class="title">Fields</h2>
<dl>
<dt id="mongoid.props.id"><var class="varname"><var class="varname">$id</var></var></dt>
<dd>
<span class="simpara">
This field contains the string representation of this object.
</span>
<blockquote class="note"><p><strong class="note">Note</strong>:
<span class="simpara">
The property name begins with a <em>$</em> character. It may
be accessed using
<a href="language.types.string.html#language.types.string.parsing.complex" class="link">complex variable
parsed syntax</a> (e.g. <em>$mongoId->{'$id'}</em>).
</span>
</p></blockquote>
</dd>
</dl>
</div>
<div class="section">
<h2 class="title">See Also</h2>
<p class="para">
MongoDB core docs on <a href="https://docs.mongodb.com/manual/reference/object-id/" class="link external">» ObjectIds</a>.
</p>
</div>
</div>
<h2>Table of Contents</h2><ul class="chunklist chunklist_reference"><li><a href="mongoid.construct.html">MongoId::__construct</a> — Creates a new id</li><li><a href="mongoid.gethostname.html">MongoId::getHostname</a> — Gets the hostname being used for this machine's ids</li><li><a href="mongoid.getinc.html">MongoId::getInc</a> — Gets the incremented value to create this id</li><li><a href="mongoid.getpid.html">MongoId::getPID</a> — Gets the process ID</li><li><a href="mongoid.gettimestamp.html">MongoId::getTimestamp</a> — Gets the number of seconds since the epoch that this id was created</li><li><a href="mongoid.isvalid.html">MongoId::isValid</a> — Check if a value is a valid ObjectId</li><li><a href="mongoid.set-state.html">MongoId::__set_state</a> — Create a dummy MongoId</li><li><a href="mongoid.tostring.html">MongoId::__toString</a> — Returns a hexidecimal representation of this id</li></ul>
</div>
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