QuickBooks/Utilities.php
public static function hasQuickBooksID($dsn, $user, $object_type, $app_ID)
	{
		if (QuickBooks_Utilities::fetchQuickBooksID($dsn, $user, $object_type, $app_ID))
		{
			return true;
		}
		
		return false;
	}
public static function hasQuickBooksID($dsn, $user, $object_type, $app_ID)
	{
		if (QuickBooks_Utilities::fetchQuickBooksID($dsn, $user, $object_type, $app_ID))
		{
			return true;
		}
		
		return false;
	}
Tell whether or not a given object has a ListID or TxnID associated with it

* Note *
This function *does not* query QuickBooks, it only queries the internal
mapping of QuickBooks IDs to PRIMARY KEYS. The mappings can be created
with the {@link QuickBooks_Utilities::createMapping()} method and the API
tries to automatically create the mapping when you add or update an
object and provide a PRIMARY KEY when calling the ->add* or ->update*
method.

@param string $object_type
@param mixed $app_ID
@return boolean