Question

I’m after some code advice. I’ve got two models which are dependent on each other. When one of the models gets deleted I want to make sure both records in the database are deleted.

I handle this in one direction using foreign keys so if the parent gets deleted to. But as these rows are both dependent on each other I need the same functionality to happen in the child.

In the child model I’ve overloaded the delete method so it looks like this:

    public function delete() {

    $cameraTransaction = $this->dbConnection->beginTransaction();

    try
    {
        $this->ftpuser->delete();
        if($this->beforeDelete())
        {
            $result=$this->deleteByPk($this->getPrimaryKey())>0;
            $this->afterDelete();
        }
        $cameraTransaction->commit();
    }
    catch(Exception $e) // an exception is raised if a query fails
    {
        $cameraTransaction->rollBack();
    }

}

I’ve tested and this seems to work well. I wondered if an expert / guru could confirm whether I’ve done the right thing 🙂

Thanks

Alan

Answer 1

I think you are doing it right. You can make it something more general.

Every model has relations defined, make some(or all) the relations deletable. You have to flag them ( in someway) deletable along with current record.

I would define a new function besides relations() in the model.

function deletableRelations() {
    return array('ftpuser', 'childs', .....);
}

and define some generic function (please include DB transactions in this function.)

function DeleteRelationships($model) {
    foreach( $model->deletableRelations() as $relation ) {
        if( $model->$relation == null) continue;

        if( is_array($model->$relation)) {
            foreach( $model->$relation as $relRecord ) {
                $relRecord->delete();
            }
        }
        else {
            $model->$relation->delete();
        }
    }
}

And this generic function can be used any of your models.
Make sure that recursion does not happen here (i.e. parent deletes child … but child also tries to delete parent. )