2 foreign keys referencing same primary key laraavel - mysql

Question

I'm relatively new in Laravel and I would like to learn how to create recursive relation with 2 foreign keys referencing the primary key.
I have table item_associations which has 2 FK referenced to the item table's PK:
Schema::create('item_associations', function (Blueprint $table) {
$table->increments('id');
$table->timestamps();
$table->unsignedInteger('item_id');
$table->foreign('item_id')
->references('id')
->on('items');
$table->unsignedInteger('item2_id');
$table->foreign('item2_id')
->references('id')
->on('items');
});
Here is my ItemAssociation model:
protected $table = 'item_associations';
public function items(){
return $this->belongsTo('App\Models\Item','item_id');
}
public function item2_id(){
return $this->belongsTo('App\Models\Item','item2_id', 'item_id');
}
here is my Item model:
protected $table = 'items';
public function item_associations(){
return $this->hasMany(UserType::class);
}
here is my Welcome controller:
$item_association = DB::table('item_associations')
->join ('items', 'item_associations.item_id', '=', 'items.id')
->join ('items', 'item_associations.item2_id', '=', 'items.id')
->get();
return view('welcome', [
'item_association' => $item_association,
]);
Apparently, I receive an error:
SQLSTATE[42000]: Syntax error or access violation: 1066 Not unique table/alias: 'items' (SQL: select * from item_associations inner join items on item_associations.item_id = items.id inner join items on item_associations.item2_id = items.id)
in blade I would like to get something like this:

Answer 1

What if you want to add another thing besides gravies?
I can suggest you 2 options.
First, instead of creating foreign keys in the separate columns, keep ids in a column by casting them an array. This is easy to setup and very flexible way.
Second, which is a better way in my opinion, using proper eloquent relationships like following:
The structure you want to achieve is a form of many-to-many relationship.
You need 3 tables: items, associations, association_item.
// Models/Item.php
public function associations()
{
return $this->belongsToMany(Association::class);
}
// Models\Association.php
public function items()
{
return $this->belongsToMany(Item::class);
}
public function additions()
{
return $this->hasMany($this, 'parent_id', 'id');
}
// Migrations
Schema::create('items', function (Blueprint $table) {
$table->increments('id');
// some fields
$table->timestamps();
});
Schema::create('associations', function (Blueprint $table) {
$table->increments('id');
// some fields
$table->foreingId('parent_id')->nullable()->costrained('assosiations')
$table->timestamps();
});
Schema::create('association_item', function (Blueprint $table) {
$table->increments('id');
$table->foreignId('item_id');
$table->foreingId('association_id');
$table->timestamps();
});