Cakephp 3: Set virtual property with condition on belongsToMany association - php

Question

I have two tables, Tickets and Paintings. A ticket can have many paintings and a painting can be used on many tickets. They have a join table called tickets_paintings with ticket_id and painting_id. Here's how the tables are set:
class TicketsTable extends Table
{
public function initialize(array $config)
{
$this->belongsToMany('Paintings', [
'foreignKey' => 'ticket_id',
'targetForeignKey' => 'painting_id',
'joinTable' => 'tickets_paintings'
]);
}
class PaintingsTable extends Table
{
public function initialize(array $config)
{
$this->belongsToMany('Tickets', [
'foreignKey' => 'painting_id',
'targetForeignKey' => 'ticket_id',
'joinTable' => 'tickets_paintings'
]);
}
Every Ticket has a field "active" that is boolean and tells me if the ticket is currently in use or not. In the edit function the field can be changed to true or false.
But now I also need a property for every Painting, that tells me if this painting is currently used on an active ticket. In this case it would be unavailable to be used on another ticket.
I thought I could add a boolean virtual property for a painting, that checks if it is (currently) associated with any ticket that has active => true and is therefore also set true or false.
Like: "Does this painting belong to a ticket with state active => 0".
And then set the virtual property accordingly, so I can display it in a view.
I managed to create a virtual property for a painting that checks if there is an entry for its ID inside the join table so far:
class Painting extends Entity
{
protected function _getIsAvailable(){
$TicketsTable = TableRegistry::get('TicketsPaintings');
$exists = $TicketsTable->exists(['painting_id' => $this->id]);
if($exists == true){
return 1;
} else {
return 0;
}
}
}
A) How could I add a condition that checks if any matching ticket_id in the join table has an active=> 1 in the original Tickets table?
The query would have to check the ticket_id in the join table in an DESC order and return true as soon as the first active ticket is found (so it does not check the whole thing every time)
I don't even understand how to access that "active" property on the tickets table to check it. I assume I would have to use the " has Many through" option?! But even trying to following the explanation in the book and this question exactly (for hours), I am not able to get this to work for my example because I don't understand the correct syntax I had to use for my tables.
B) Is it even possible or "advisable" to check sth like this inside the Entity?
I tried to use an extra db field in the paintings table first but it seemed much more complicated to check and set another value every time a ticket is edited (not that I managed to make that work either)...and the active value is pretty much doubled then for ticket and painting. So I thought the virtual property would be easier to handle. Or am I on the completely wrong train?
Thanks for any tips or advice on this nightmare =)!

Answer 1

Since nobody came to my rescue I managed to put something together and actually create the virtual property I wanted. I don't know if this is the best way to go but it works for me and I will put it here in case anyone is searching for similar case.
I created a finder method inside the Paintings Table that joins the 3 tables and filters out all paintings that are connected to an active ticket.
class PaintingsTable extends Table
{
public function findNotavailable(Query $query, array $options){
$query
->join([
'tickets_paintings' =>[
'table' => 'tickets_paintings',
'type' => 'LEFT',
'conditions' => 'tickets_paintings.painting_id = Paintings.id'
],
'tickets' => [
'table' => 'tickets',
'type' => 'LEFT',
'conditions' => 'tickets_paintings.ticket_id = Tickets.id'
],
])
->select(['Paintings.id'])
->order(['tickets_paintings.ticket_id' => 'DESC'])
->where([
'Tickets.active' => false
]);
return $query;
}
}
Then in the Entity of the Painting I check if its ID is inside this selection and set a boolean virtual property accordingly:
use Cake\ORM\TableRegistry;
class Painting extends Entity
{
protected function _getNotAvailable(){
$Paintings = TableRegistry::get('Paintings');
$notavailable = $Paintings->find('notavailable')
->where(['Paintings.id'=>$this->id]);
if($notavailable->isEmpty()){
// if no record --> painting is available
return 0;
} else {
// if record found --> painting is not available
return 1;
}
}
}
And in the view I display it like this:
In Paintings - view.ctp
<?= $painting->not_available ? __('not available') : __('available'); ?>
The only downside to it is that virtual properties can't be used for pagination as far as I understand the book. But I'm sure there's a workaround for that too.