note 110746 modified in mongocollection.save by danbrown

Same as with method insert(), it is worth noting that creating a reference to $obj will have the same effect as $obj being a reference itself, i.e. no _id field will be added. <?php $a = &$obj; $m = new MongoClient; $collection = $m->test->phpmanual; $obj = array('x' => 1); // Suppose you create a reference for some reason $a = &$obj; $collection->save($obj); var_dump($obj); // prints: array(1) { ["x"]=> int(1) } ?> --was-- Same as with method insert(), it is worth noting that creating a reference to $obj will have the same effect as $obj being a reference itself, i.e. no _id field will be added. <?php $a = &$obj; $m = new MongoClient; $collection = $m->test->phpmanual; $obj = array('x' => 1); // Suppose you create a reference for some reason $a = &$obj; $collection->save($obj); var_dump($obj); // prints: array(1) { ["x"]=> int(1) } http://php.net/manual/en/mongocollection.save.php