Delete/detach first pivot table records - php

Question

Case
Laravel 5.3
Having a pivot table between Cart & Product with an additional column:
id - cart_id - product_id - item_id (additional column)
1 - 1 - 1 - 5
2 - 1 - 1 - 6
3 - 1 - 1 - 7
4 - 2 - 1 - 8
Normally you detach a pivot table record using:
$product->carts()->detach($cartId);
But in this case, there are several pivot table records with the same cart & product id
Problem
Lets say I want delete to row 1.
What I hoped to work was either one of these:
$product->carts()->detach($itemId);
or
$product->carts()->detach($cartId)->first();
If I query the pivot table based on cart_id & product_id, call the first & run delete() on that query result a Call to undefined method stdClass::delete() will be returned
$firstItem = DB::table('cart_product')
->where('cart_id', $cart_id)
->where('product_id', $product->id)
->first();
$firstItem->delete();
Although when I dd() $firstItem after querying the data, it will return a (correct) object
{#238 ▼
+"id": 1
+"cart_id": 1
+"product_id": 1
+"item_id": 5
}

Answer 1

You can't use detach() if you want to delete just one row in this table.
If you want to delete just first item, just use this:
DB::table('cart_product')
->where('cart_id', $cart_id)
->where('product_id', $product->id)
->take(1)
->delete();
Or from your code:
$id = DB::table('cart_product')
->where('cart_id', $cart_id)
->where('product_id', $product->id)
->first()->id;
DB::table('cart_product')
->where('id', $id)
->delete();