Pfthb

I am having an issue getting a hasManyThrough to work:

public function deliveryContainers() : HasManyThrough

 return $this->hasManyThrough(
 DeliveryContainer::class, // Final
 StockMovement::class, // Intermediate
 'product_id', // Foreign key on Intermediate
 'id', // Foreign key on Final
 'product_id', // Local key on Current
 'location_id' // Local key on Intermediate
 )->where('delivery_id', $this->delivery_id);

Because the stockMovements table returns multiple results, my resulting delivery containers collection contains duplicate entries. If I could somehow put a group/unique on the intermediate table query then this would be resolved.

I can get a collection with the correct deliveryContainers eager loaded using the following:

public function deliveryContainers()

 return $this->hasMany(StockMovement::class, 'entity_id', 'delivery_id')
 ->with('deliveryContainer')
 ->where('product_id', $this->product_id)
 ->get()
 ->unique('location_id');

However, to access the deliveryContainer I now have the following:

foreach($this->deliveryContainers() as $row)
 $row->deliveryContainer->id; 

And what I would like to have...

foreach($this->deliveryContainers() as $row)
 $row->id;

Is there any way to push the eager loaded relationship up a level (if that can be used to describe it), or even better add some kind of unique filter to the hasManyThrough relationship?

Table Structure

delivery_exceptions (where this relationship originates)

• product_id


• delivery_id

delivery_containers

• id


• delivery_id

stock_movements

• entity_id (linked to delivery id)


• product_id

Relationships

• A delivery exception belongsTo a product


• A product hasMany stock_movements


• A stock movement belongsTo a delivery container
  


• A delivery exception hasMany delivery containers... (indirectly, through a combination of the product and the stock movements)

You've got a really tough setup there and I'm not entirely sure that I got the full idea behind it (also because of you using entity_id at some place instead of delivery_id). But nonetheless, I gave it a shot.

The hasManyThrough relationship you defined looks actually not too bad, but in my opinion there is a better way to get to the result. But first let's have a look at your relationships:

 3
 +-------------------------------------+
 4 v |
 +-------------> Delivery <----------+ |
 | | 1 |
 + + +
DeliveryException +---> Product <---+ StockMovement +---> DeliveryContainer
 + ^
 +---------------------------------------------------------+
 2

As a StockMovement already belongs to a DeliveryContainer, which in return belongs to a Delivery, the relation from StockMovement to Delivery (marked as 1) seems obsolete to me. Anyway, to get relation 2 on your model, you can use the paths 3 and 4 to your advantage:

class DeliveryException

 public function deliveryContainers(): HasMany
 
 return $this->hasMany(DeliveryContainer::class, 'delivery_id', 'delivery_id');
 

Obviously, this will give you all the DeliveryContainers, unfiltered by the Product. Therefore I suggest adding a second function:

public function deliveryContainersByProduct(): HasMany

 return $this->deliveryContainers()
 ->whereHas('stockMovements', function ($query) 
 $query->where('product_id', $this->product_id);
 );

The accepted answer is far more elegant, but this is another way to do this too:

public function deliveryContainers1()

 return $this->hasManyThrough(
 DeliveryContainer::class, // Final
 StockMovement::class, // Intermediate
 'product_id', // Foreign key on Intermediate
 'id', // Foreign key on Final
 'product_id', // Local key on Current
 'location_id' // Local key on Intermediate
 )
 ->where('delivery_id', $this->delivery_id)
 ->distinct();