(PECL mongo >= 0.8.0)
MongoId::__construct — Creates a new id
A string to use as the id. Must be 24 hexidecimal characters. If an invalid string is passed to this constructor, the constructor will ignore it and create a new id value.
Returns a new id.
Example #1 MongoId::__construct() example
This example shows how to create a new id. This is seldom necessary, as the driver adds an id to arrays automatically before storing them in the database.
<?php
$id1 = new MongoId();
echo "$id1\n";
$id2 = new MongoId();
echo "$id2\n";
?>
以上例程的输出类似于：
49a7011a05c677b9a916612a 49a702d5450046d3d515d10d
Example #2 Parameter example
This example shows how to use a string parameter to initialize a MongoId with a given value.
<?php
$id1 = new MongoId();
// create a new id from $id1
$id2 = new MongoId("$id1");
// show that $id1 and $id2 have the same hexidecimal value
var_dump($id1 == $id2);
?>
以上例程的输出类似于：
bool(true)