**

**OrdersTable***

        $this->belongsToMany('Products',[
                'through'=>'OrderLines',
                'foreignKey'=>'order_id',
                'bindingKey'=>'id',
            ]);
            
**OrderLinesTable**
        $this->belongsTo('Orders', [
            'foreignKey' => 'order_id'
        ]);
        
        $this->belongsTo('Products',[
            'foreignKey' => 'sku',
            'bindingKey' => 'sku',
        ]);
        
**ProductsTable**
 $this->belongsToMany('Orders',
            [
                'through'=>'OrderLines',
                'foreignKey'=>'sku',
                'bindingKey'=>'sku',
            ]);