Storing Values in a Polymorphic Pivot Table

Hello. I want to store values in a Polymorphic HasMany relationship.

I have the following three tables:

• Shows
• Attributes
• Attributables

Attributables stores the polymorphic relationship between Shows and Attributes. It looks like this.

• attribute_id
• attributable_id
• attributable_type
• attributable_value

Now, in a regulal polymorphic relationship, we only use the first three columns. I added the attributable_value myself. I would like to store a value here for that specific relationship between Shows and Attributes. How can I cast this onto my models (e.g. Show, Movie, etc.)? How can I save it when creating the relationship?

I started with making a trait to add the attributable behavior to any models requiring it and created an Attribute model. Do I need to expand on the relationship code already written in the framework?

Any help is appreciated.

UPDATE: I discovered how to save the attributable_value but don't know how to retrieve it without writing additional queries.

$show = App\Models\Show::find(1);

$attribute = new \Waran\Models\Attribute;
$attribute->name = 'Size';

$show->attributes()->save($attribute, ['attributable_value' => 'large']);

Any ideas on how to retrieve the attributable_value when performing the polymorphic query $shows->attributes()?