How to create a cart model in prisma in relation with user and product models?

Question

I have a product and user model in schema.prisma.

type Photo {
  height Int
  width  Int
  url    String
}

model User {
  id         String    @id @default(auto()) @map("_id") @db.ObjectId
  email      String    @unique
  password   String
  products   Product[]
  role       Role
  profileImg Photo
}


model Product {
  id            String            @id @default(auto()) @map("_id") @db.ObjectId
  name          String
  price         Int
  stock         Int
  createdAt     DateTime          @default(now())
  updatedAt     DateTime          @updatedAt
  user          User              @relation(fields: [userId], references: [id])
  userId        String            @db.ObjectId
  brand         String
}

Now, I want to make a cart model which will have two fields one for the user and another for cartItems. Its type should be like

type cartItems = {product: Product, quantity: number}[]

Now how do I create the cart model for this. since I can't write like this

type CartItem {
  product: Product
  quantity: Int
}

model Cart {
  id        String  @id @default(auto()) @map("_id") @db.ObjectId
  userId    String     @db.ObjectId
  user      User       @relation(fields: [userId], references: [id])
  cartItems CartItem[]
}

because composite type can't have relations. One way I can do it, is by changing CartItem type to this

type cartItem {
  productId  String @db.ObjectId
  quantity Int
}

But, in this case, for getting products in cart items, a separate request need to be made with the productId.

Is there any better solution?

Answer 1

You could use a groupby with callback and return the id based on sequence. As there is no overlap in the size of your ranges the best approach might be to just hardcode the if-else structure. A little prettier could be to make an array out of it e.g.

$ranges = [
    [
        'min' => 1
        'max' => 4,
    ],
    ...
];

Answer 2

I'd say the cleaner way would be to change your table as to include a "min" and "max" column. This way, you'll be able to easily get the expected result with an SQL request (giving you the option to use it on your Models too)

If you do so, your request will look something like this and give you the expected result :

"SELECT * FROM sequence_table WHERE $sequence > sequence_table.min AND $sequence < sequence_table.max"