How to create a self BelongsToMany relation in CakePHP 3 - cakephp

Question

I have a database with a table "projekte" (german word for projects).
Some of the projects have a relation to eachother.
So i would like to have a BTM relation.
I created a joinTable "projektverbindungen" with the following fields:
projekt_id
nebenprojekt_id
I found a similar question here: BelongstoMany relationship between a table and itself and i tried the answer of ndm, but without success.
Here is my ProjekteTable.php
class ProjekteTable extends Table {
public function initialize(array $config)
{
parent::initialize($config);
$this->setTable('projekte');
$this->setDisplayField('name');
$this->setPrimaryKey('id');
$this->hasOne('Projekteigenschaften', [
'foreignKey' => 'projekt_id',
'dependent' => true,
]);
$this->belongsToMany('Projekte', [
'foreignKey' => 'projekt_id',
'targetForeignKey' => 'nebenprojekt_id',
'joinTable' => 'projektverbindungen',
]);
}
}
Here ist my template (add.ctp)
<?php
echo $this->Form->create($projekt);
echo $this->Form->control('name', ['class' => 'form-control']);
echo $this->Form->control('projekteigenschaft.projektverantwortlich');
echo $this->Form->control('projekteigenschaft.beschreibung');
echo $this->Form->control('projekte._ids', ['options' => $projekte, 'multiple' => true]);
echo $this->Form->button(__('Submit'));
echo $this->Form->end();
?>
The first step, saving a project with a related project works as expected.
The id of the created project was saved as projektverbindungen.projekt_id and the id of the related project as projektverbindungen.nebenprojekt_id.
When i query a projekt without the relation to other projects like so:
$projekt = $this->Projekte->get($id, [
'contain' => ['Projekteigenschaften']
]);
the query looks like this:
SELECT Projekte.id AS `Projekte__id`, Projekte.name AS `Projekte__name`, Projekteigenschaften.id AS `Projekteigenschaften__id`, Projekteigenschaften.projektverantwortlich AS `Projekteigenschaften__projektverantwortlich`, Projekteigenschaften.beschreibung AS `Projekteigenschaften__beschreibung`, Projekteigenschaften.projekt_id AS `Projekteigenschaften__projekt_id` FROM projekte Projekte LEFT JOIN projekteigenschaften Projekteigenschaften ON Projekte.id = (Projekteigenschaften.projekt_id) WHERE (Projekte.id = :c0 AND (Projekte.deleted) IS NULL)
And the debug of the result looks like:
"id": "6862279f-8134-401f-86ff-9278a3bfa5c3",
"name": "My Project",
"projekteigenschaft": {
"id": "89d9e241-e700-4c31-9266-ee5717f2a0aa",
"projektverantwortlich": "Blisginnis, Ralf",
"beschreibung": ""
}
Everything works fine.
But when i add the projects to contain like so:
$projekt = $this->Projekte->get($id, [
'contain' => ['Projekteigenschaften', 'Projekte']
]);
The query looks the same like above, but the entity looks a bit different:
"Projekteigenschaften": {
"id": "89d9e241-e700-4c31-9266-ee5717f2a0aa",
"projektverantwortlich": "Blisginnis, Ralf",
"beschreibung": ""
}
Projekteigenschaften seems no longer to be a hasOne relation and "Projekte" gets totally ignored.
Anyone has an idea what i did wrong? Or should i prefer an other way of doing this?
edit after ndm´s comment
I tried defining the relationship like so:
$this->belongsToMany('Projektverbindungen', [
'class' => 'Projekte',
'foreignKey' => 'projekt_id',
'targetForeignKey' => 'nebenprojekt_id',
'joinTable' => 'projektverbindungen',
]);
and changed the add.ctp template like so:
echo $this->Form->control('projektverbindungen._ids', ['options' => $projekte, 'multiple' => true]);
But then it doesn´t save the relation.
I also tried to rename the joinTable to projekte_projekte. It didn´t seem to make any difference.
Then I tried to use the through-option, but the results of that were even worse.
So I continued trying to find a solution with the method described above.
2nd edit
projekverbindungen ist accessible in Projekt.php:
protected $_accessible = [
'name' => true,
'projekteigenschaft' => true,
'projekte' => true,
'projektverbindungen' => true,
];
Debug of requestData:
[
'name' => 'My Project',
'projekteigenschaft' => [
'projektverantwortlich' => 'John Doe',
'beschreibung' => '',
'projektverbindungen' => [
'_ids' => [
(int) 0 => '809031f2-4ecd-4dfb-82d5-2c911286dd21'
]
]
]
Debug of entity after patching:
object(App\Model\Entity\Projekt) {
'name' => 'My Project',
'projekteigenschaft' => object(App\Model\Entity\Projekteigenschaft) {
'projektverantwortlich' => 'John Doe',
'beschreibung' => '',
'[new]' => true,
'[accessible]' => [
'projektverantwortlich' => true,
'beschreibung' => true,
'projekt_id' => true,
'projekt' => true
],
'[dirty]' => [
'projektverantwortlich' => true,
'beschreibung' => true
],
'[original]' => [],
'[virtual]' => [],
'[hasErrors]' => false,
'[errors]' => [],
'[invalid]' => [],
'[repository]' => 'Projekteigenschaften'
},
'projektverbindungen' => [],
'[new]' => true,
'[accessible]' => [
'name' => true,
'projekteigenschaft' => true,
'projekte' => true,
'projektverbindungen' => true
],
'[dirty]' => [
'name' => true,
'projekteigenschaft' => true,
'projektverbindungen' => true
],
'[original]' => [],
'[virtual]' => [],
'[hasErrors]' => false,
'[errors]' => [],
'[invalid]' => [],
'[repository]' => 'Projekte'
}
3rd edit
In my bootstrap.php i have this:
Inflector::rules('plural', [
'/^(projekt)$/i' => '\1e',
'/^(projekteigenschaft|projektverbindung)$/i' => '\1en',
]);
Inflector::rules('singular', [
'/^(projekt)e$/i' => '\1',
'/^(projekteigenschaft|projektverbindung)en$/i' => '\1',
]);
After your recommendation I additionally added propertyName to the definition of the association:
$this->belongsToMany('Projektverbindungen', [
'class' => 'Projekte',
'propertyName' => 'Projektverbindungen',
'foreignKey' => 'projekt_id',
'targetForeignKey' => 'nebenprojekt_id',
'joinTable' => 'projektverbindungen',
]);
After that, the patched entity looks like this:
object(App\Model\Entity\Projekt) {
'name' => 'My Project',
'projekteigenschaft' => object(App\Model\Entity\Projekteigenschaft) {
'projektverantwortlich' => 'John Doe',
'beschreibung' => '',
'[new]' => true,
'[accessible]' => [
'projektverantwortlich' => true,
'beschreibung' => true,
'projekt_id' => true,
'projekt' => true
],
'[dirty]' => [
'projektverantwortlich' => true,
'beschreibung' => true
],
'[original]' => [],
'[virtual]' => [],
'[hasErrors]' => false,
'[errors]' => [],
'[invalid]' => [],
'[repository]' => 'Projekteigenschaften'
},
'projektverbindungen' => [
'_ids' => [
(int) 0 => '1e28a3d1-c914-44be-b821-0e87d69cd95f'
]
],
'[new]' => true,
'[accessible]' => [
'name' => true,
'projekteigenschaft' => true,
'projekte' => true,
'projektverbindungen' => true
],
'[dirty]' => [
'name' => true,
'projekteigenschaft' => true,
'projektverbindungen' => true
],
'[original]' => [],
'[virtual]' => [],
'[hasErrors]' => false,
'[errors]' => [],
'[invalid]' => [],
'[repository]' => 'Projekte'
}
But still no new entry in the table "projektverbindungen"

Answer 1

The last suggestion of ndm made the trick.
Now it works like expected. Thank you very much!
Here is the correct setup:
ProjekteTable.php
$this->belongsToMany('Nebenprojekte', [
'className' => 'Projekte',
'foreignKey' => 'projekt_id',
'targetForeignKey' => 'nebenprojekt_id',
'joinTable' => 'projektverbindungen',
]);
Here I used the property class instead of className, that has been the biggest issue.
Thats really embarrassing, because in the Cookbook is the correct name of that property:
https://book.cakephp.org/3/en/orm/associations.html#belongstomany-associations
Nevertheless, perhaps anyone else makes the same mistake and this thread can help.
The second thing is not to use the jointable`s name as the name of the association.
The rest is just straight forward...
Making the association accessible in the Entity Class (Projekt.php):
protected $_accessible = [
'name' => true,
'projekteigenschaft' => true,
'nebenprojekte' => true,
];
ProjekteController.php ("add" and "edit"):
public function add()
{
$projekt = $this->Projekte->newEntity();
if ($this->request->is('post')) {
$projekt = $this->Projekte->patchEntity($projekt, $this->request->getData());
if ($this->Projekte->save($projekt)) {
$this->Flash->success(__('flash message'));
return $this->redirect(['action' => 'index']);
}
$this->Flash->error(__('error message'));
}
$projekte = $this->Projekte->find('list');
$this->set(compact('projekt', 'projekte'));
}
public function edit($id = null)
{
$projekt = $this->Projekte->get($id, [
'contain' => ['Projekteigenschaften', 'Nebenprojekte']
]);
if ($this->request->is(['patch', 'post', 'put'])) {
$projekt = $this->Projekte->patchEntity($projekt, $this->request->getData());
if ($this->Projekte->save($projekt)) {
$this->Flash->success(__('flash message'));
return $this->redirect(['action' => 'index']);
}
$this->Flash->error(__('error message'));
}
$projekte = $this->Projekte->find('list')->where(['id !=' => $id]);
$this->set(compact('projekt', 'projekte'));
}
In the templates like add.ctp or edit.ctp:
echo $this->Form->control('nebenprojekte._ids', ['options' => $projekte, 'multiple' => true]);
If you use another language than english, don´t forget to set the correct inflection rules.
bootstrap.php:
Inflector::rules('plural', [
'/^(projekt|nebenprojekt)$/i' => '\1e',
'/^(projekteigenschaft)$/i' => '\1en',
]);
Inflector::rules('singular', [
'/^(projekt|nebenprojekt)e$/i' => '\1',
'/^(projekteigenschaft)en$/i' => '\1',
]);