Returning database resources as references from within a class? Help?

[jasonla]

Let's suppose I have a class that encompasses a function such as this:

class SomeClass
{
   var $db_resource;

   function &db_connect()
   {
      $this->db_resource =& database_connect($host, $user,$pass, $dbname);

  return $this->db_resource;
   }
}

And then I create a new instance like this:

$instance = new SomeClass;
$my_connection =& $instance->db_connect();

My two questions are:

1) Is $my_connection the exact same resource as $this->db_resource? Or am I just making copies of resources? Or is $my_connection a reference to a reference ($this->db_resource).

2) Is it more efficient to use references in this way, rather than make copies?

I understand C++ pointers and such, but as I have read, PHP's references aren't exactly like that.

[ahundiak]

1. Yes, it's the same resource. You might take the time to actually test this by setting a value in $db and then seeing if it's reflected inside of $instance.

2. It's usually better to use references just so you don't get surprised by a copy's behaviour.

For the zend implementation of php, there is actually no difference between using references and copies until you actually make a change to an object's instance data. Updating an object will trigger an actual copy to be made. So as long as the object remains unchanged then you don't really need references. But again, it's usually safer to do so.