Return json with data from three tables in Laravel

Question

//CartController
$itens = CartItem::where('id_cart', $cart->id)->with('product')->get();
return response()->json($itens);

This code returns a JSON with the data of the cart item and the relative product. But I also want to return the images of the product, which is in the ProductImages table.

In my model CartItem.php I have

 public function product(){
    return $this->belongsTo('App\Product', 'id_product');
}

In my model Product.php I have

  public function images(){
    return $this->hasMany('App\ProductImages', 'id_product');
}

But, if I do

 $itens = CartItem::where('id_cart', $carrinho->id)->with('product')->with('image')->get();

I get the error

Call to undefined relationship [images] on model [App\CartItem]

Answer 1

You can try it as:

CartItem::where('id_cart', $carrinho->id)->with('product.images')->get();

To eager load nested relationships, you may use "dot" syntax.

Docs

Answer 2

You should load two tables by using with():

CartItem::where('id_cart', $cart->id)
        ->with('product', 'product.images')
        ->get();

You can read an explanation here (see Nested Eager Loading section).