/**
* Check if there are changes between old and new value for this field
*
* @param Tracker_Artifact_ChangesetValue $old_value The data stored in the db
* @param array $new_value array of artifact ids
*
* @return bool true if there are differences
*/
public function hasChanges(Tracker_Artifact_ChangesetValue $old_value, $new_value)
{
return $old_value->hasChanges($new_value);
}