CakePHP: Retreiving a column from the join table in a belongsToManay relationship - php

Question

My application allows a user to create scenarios by linking together soe_blocks. In turn, soe_blocks refer to a variable number of soe_entries.
To build scenarios, soe_blocks are linked to the scenario and ordered by an offset. The soe_blocks can be used in many different scenarios. soe_entries can relate only to a single soe_block
I think the relationship is defined as:
scenarios belongsToMany soe_blocks through scenarios_soe_blocks
soe_blocks belongsToMany scenarios through scenarios_soe_blocks
scenarios_soe_blocks is where the offset is kept
soe_entries haveOne soe_blocks
Tables:
scenarios: id | name
data: 0, 'scenario_1'
soe_blocks: id | name
data: 0, 'soe_block_1'
1, 'soe_block_2'
scenarios_soe_blocks: id | scenario_id | soe_block_id | offset
data: 1, 0, 1, 1
2, 0, 2, 2
Models:
class ScenariosTable extends Table
{
$this->belongsToMany('SoeBlocks', [
'foreignKey' => 'scenario_id',
'targetForeignKey' => 'soe_block_id',
'through' => 'ScenariosSoeBlocks',
'joinTable' => 'soe_blocks'
]);
}
class SoeBlocksTable extends Table
{
$this->belongsToMany('Scenarios', [
'foreignKey' => 'soe_block_id',
'targetForeignKey' => 'scenario_id',
'joinTable' => 'scenarios_soe_blocks',
'through' => 'ScenariosSoeBlocks'
]);
}
class ScenariosSoeBlocksTable extends Table
$this->belongsTo('SoeBlocks', [
'foreignKey' => 'soe_block_id',
'joinType' => 'INNER'
]);
}
Controllers:
public function view($id = null)
{
$scenario = $this->Scenarios->get($id, [
'contain' => ['SoeBlocks', 'RunStatus', 'ScenarioLog']
]);
$this->set('scenario', $scenario);
}
As far as I can make out from CakePHP Doc, this is all I need. But I couldn't get the ScenarioController->view() method to return the offsets from the scenarios_soe_blocks table associated with the soe_blocks.
I tried to add ScenariosSoeBlocks into the 'contain' clause in the ScenarioController, but got the error: Scenarios is not associated with ScenariosSoeBlocks. I found an SO article that suggested I add the following to the ScenarioTable:
$this->hasMany('ScenariosSoeBlocks', [
'foreignKey' => 'scenario_id'
]);
This seems to have worked, and now I can request ScenariosSoeBlocks in my controller like this:
$scenario = $this->Scenarios->get($id, [
'contain' => ['SoeBlocks', 'ScenariosSoeBlocks', 'RunStatus', 'ScenarioLog']
]);
Which at least gets the data into the view template, but not in the single object I'm hoping for. Eventually, I want to be able to CRUD the soe_blocks along with their associated soe_entries, in an object that looks like this:
offset | soe_block_id | soe_entry_id |
I have many other questions, like how to save etc., but I figured I need to get this working first.
So, my questions for now are:
are my associations correct?
how do I retrieve all the associations to view?

Answer 1

are my associations correct?
The first two are, but then it should be:
soe_blocks hasOne soe_entries
soe_entries belongsTo soe_blocks
how do I retrieve all the associations to view?
By containing them, just like you did in your first example. This question seems to originate from the question how to access the join table data, which is very simple, the join table data is being set on the target table entity (Scenario or SoeBlock, depending on from which side/table you issue the query), in a property named _joinData:
$joinTableEntity = $scenario->soe_blocks[0]->_joinData;
$offset = $joinTableEntity->offset;
You can easily gather information about the data structure by dumping your entity contents:
debug($scenario);
See also
Cookbook > Database Access & ORM > Associations - Linking Tables Together
Cookbook > Database Access & ORM > Saving Data > Saving Additional Data to the Join Table