'integer', 'discount' => 'integer', 'shipping_cost' => 'integer', 'total' => 'integer', ]; } public function createdBy(): BelongsTo { return $this->belongsTo(User::class, 'created_by_id'); } public function purchaseItems(): HasMany { return $this->hasMany(PurchaseItem::class); } public function supplier(): BelongsTo { return $this->belongsTo(Supplier::class); } }