pivot table relationship Laravel - php

Question

I have the following relation:
RAB hasMany products.
products belongsToMany RAB
but this products also hasMany currency that belongsToOne RAB itself.
it looks like this.
in RAB model:
public function products()
{
return $this->belongsToMany('App\ModelKeuangan\ProductsModel', 'rab_products', 'rab_id', 'products_id');
}
in products model:
public function rab()
{
return $this->belongsToMany('App\ModelUnitKerja\Perencanaan\RabModel', 'rab_products', 'products_id', 'rab_id');
}
rab_products is my intermediate/join table.
it works just fine when im syncing products data for RAB. but i cant get how to make eloquent model for syncing Currency data to rab and products.
do i need to make model for currency too? if yes, how do i define it?
my plan is make a pivot like this, but can i make relation inside pivot table?
class RabProducts extends Pivot {
//relation function to currency
}
and change my products model something like:
public function rab(){
return $this->belongsToMany('App\ModelUnitKerja\Perencanaan\RabModel')->using('App\RabProducts');
}

Answer 1

Create the currency model and add foreign_key product_id:
php artisan make:model Currency
Build the one-to-many between Product and Currency
and you need to add product_id in your currencies table.
In your Currency Model:
public function product() {
return $this->belongsTo('App\Product', 'product_id');
}
In your Product Model:
public function currencies()
{
return $this->hasMany(\App\Currency::class, 'product_id', 'id');
}
So that you can call it like this:
RAB::with(['products' => function($query) {
$query->with('currencies');
}])->get();
Unfortunately, the foreign_key between products and rabs is in pivot table, you cannot create the hasmanythrough with currency directly.
You can call the currency by products. Or you can create a pivot model, and then use hasmanythrough.