Multiple relationship fields

[prodixx]

I need to implement some product - attributes logic into my project. I have 2 models - Attribute and Product with pivot table and belongsToMany relationship between them.

The problem is that i want to display multiple repeatable fields for adding attributes on Product CRUD. This is because attributes are organized by categories like Size, Color and i want to give the user a more easy way to read/follow what attributes.

i have the following relationship on product model:

public function atributesOptions()
{
    return $this->belongsToMany(\App\Models\AttributeOption::class, 'attribute_option_product', 'product_id', 'attribute_option_id')->withPivot('extra_price', 'details')->withTimestamps();
}

public function sizeAttributes()
{
    return $this->atributesOptions()->onlySizeCategory();
}

public function colorAttributes()
{
    return $this->atributesOptions()->onlyColorCategory();
}

and the following fields definition on product CRUD:

[
    'name'      => 'sizeAttributes',
    'label'     => 'Size',
    'type'      => 'relationship',
    'tab'       => 'Atribute',
    'subfields' => [
        [
            'name' => 'extra_price',
            'type' => 'number',
            'default' => 0,
            'label' => 'Extra price',
            'wrapper' => ['class' => 'form-group col-md-4'],
        ],
        [
            'name' => 'details',
            'type' => 'text',
            'label' => 'Details',
            'wrapper' => ['class' => 'form-group col-md-4'],
        ],
    ],
    'pivotSelect' => [
        'label'       => 'Size',
        'placeholder' => 'choose size',
        'wrapper'     => ['class' => 'col-md-4'],
        'options'   => (function ($query) {
            return $query->onlySizeCategory()->get();
        }),
    ],
    'new_item_label' => 'Add size',
    'init_rows' => 1,
    'min_rows' => 1,
    'max_rows' => 4,
    'reorder' => false,
],
[
    'name'      => 'colorAttributes',
    'label'     => 'Color',
    'type'      => 'relationship',
    'tab'       => 'Atribute',
    'subfields' => [
        [
            'name' => 'extra_price',
            'type' => 'number',
            'default' => 0,
            'label' => 'Extra price',
            'wrapper' => ['class' => 'form-group col-md-4'],
        ],
        [
            'name' => 'details',
            'type' => 'text',
            'label' => 'Details',
            'wrapper' => ['class' => 'form-group col-md-4'],
        ],
    ],
    'pivotSelect' => [
        'label'       => 'Color',
        'placeholder' => 'choose color',
        'wrapper'     => ['class' => 'col-md-4'],
        'options'   => (function ($query) {
            return $query->onlyColorCategory()->get();
        }),
    ],
    'new_item_label' => 'Add color',
    'init_rows' => 1,
    'min_rows' => 1,
    'max_rows' => 4,
    'reorder' => false,
],

The only problem i cannot solve is that on creating/saving action is saves only the last repeatable in the database (in the example above i get only colors saved in database).

Any suggestion how to solve this?

Thanks.

[tabacitu]

Hmm interesting. The first thing that comes to mind is that you can use model events on your fields, to customize the saving process. That way, it's you who does the saving, instead of Backpack. So you could do:

[
    'name'      => 'sizeAttributes',
    'label'     => 'Size',
    'type'      => 'relationship',
    'tab'       => 'Atribute',
    'subfields' => [
        // ...
    ],
    'pivotSelect' => [
        // ...
    ],
    // ...
    'events' => [
        'saving' => function ($entry) {
            // TODO: your saving logic here
        },
    ],
],

But this does make me wonder... WHY?! Why does it only save the last one? It's probably because behind the scenes Backpack will turn that "fake" relationship into the "real" relationship. But... then... isn't this like sort of a bug?

What do you think @pxpm - is this worth supporting?

[o15a3d4l11s2]

The reason for this is https://github.com/Laravel-Backpack/CRUD/blob/f180f5e4bb900640f5c07abf5e1c1fbb70ccf6d7/src/app/Library/CrudPanel/Traits/Create.php#L145 which does a sync. When the last "fake" field that uses the relationship is stored, it overwrites previously stored relationships.

I do not think this is a bug, although users might expect a different behaviour.

• A "workaround" solution inside Backpack would be non-trivial, as it would need to pre-determine if such relationship-sharing fields exist. If we iterate over all relationship fields and "merge" them into relationship fields with the datas also merged, this would work.
  But there are a lot of possible structures for the relationship data, so merging would require the same value manipulations like the one in createRelationsForItem.

• Another (hacky) workaround would be something like this inside createRelationsForItem:

   // before foreach
   $populatedRelationNames = [];
   
   // inside foreach
       case 'BelongsToMany':
       case 'MorphToMany':
           $relationName = $relation->getRelationName();
           if ($relationName !== $relationMethod) {
               if (in_array($relationName, $populatedRelationNames)) {
                   $syncWithDetaching = false;
               } else {
           $populatedRelationNames[] = $relationName;
           $syncWithDetaching = true;
       }
       }
       
       // SKIPPED CURRENT LOGIC 
       
       $item->{$relationMethod}()->sync($relationValues, $syncWithDetaching);
       break;
  

  I tried this on my side and it works as expected. I have this whole user example set up, so feel free to ping me for any possible tests.

Overall I think it would be better if @prodixx adds custom logic to do this "merging" manually on create/update, probably by https://backpackforlaravel.com/docs/5.x/crud-operation-create#override-the-store-method (@tabacitu, I know you do not recommend this override 😅)

[prodixx]

thanks guys! from @o15a3d4l11s2 answer i've managed to concatenate all the inputs and do one single sync in create/update operation.

[o15a3d4l11s2]

I am happy that you were able to resolve it!