Re: check if foreign key is used in other tables before delete data row

Working with your proposed solution, I would change the code as
follows:

[code]
$rowCount = $this->Room->find(
'count', array(
'conditions' => array(
'Room.location_id' => $id
)
)
);
if ( $rowCount == 0 ) {
// Delete can take place, no children rows!
} else {
// Delete can not take place, has children rows!
}
[/code]

You should move the code to the model, so as to keep your controllers
lean and fast.

Another possibility is for you to use the counter cache, so that for
each location, there will be a counter stating how many rooms are
attached/related to it. Then you just need to check the counter
instead of querying the database.
See http://book.cakephp.org/view/816/counterCache-Cache-your-count for
more information on that!

Enjoy,
John

On Apr 2, 9:56 pm, sebb86 <kahlc...@googlemail.com> wrote:
> Hello,
>
> In an example, i want to delete a location if no rooms are associated
> to this location.
> I tryed the following:
>
> [code]
> function delete($id)
>         {
>     if(empty($this->Room->find('all', 'fields' =>
> array('Room.location_id'))))
>     {
>                   $this->Location->del($id);
>                   $this->Session->setFlash('Löschvorgang (id: '.$id.')
> erfolgreich!');
>                   $this->redirect(array ('action' => 'index'));
>     }
>     else
>     {
>       $this->Session->setFlash('Löschvorgang (id: '.$id.')
> fehlgeschlagen, da noch Räume für dieses Gebäude existieren!');
>                   $this->redirect(array ('action' => 'index'));
>     }
>         }
> [/code]
>
> Well, this dont works. I dont know how to correctly create the
> "find" :/
> Could someone help me please? Thanks!

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