Many to many relations prisma-CodePudding

I'm new to backend and stuff. I have two models: Product and City. City can have many products and product can have many cities, so I created another table ProductsOnCities:

model City {
  id            Int         @id @default(autoincrement())
  name          String
  pickupPoints  PickupPoint[]
  products      ProductsOnCities[]
}

model Product {
  id            Int         @id @default(autoincrement())
  title         String
  price         Int
  cities        ProductsOnCities[]
}

model ProductsOnCities {
  city          City        @relation(fields: [cityId], references: [id])
  cityId        Int
  product       Product     @relation(fields: [productId], references: [id])
  productId     Int

  @@id([cityId, productId])
}

How can I insert data now? For example, I want to create city with 4 products (which is already existing in my database), do I really need to create 4 objects there as it shown in prisma docs? Below is an example from the documentation.

const assignCategories = await prisma.post.create({
  data: {
    title: 'How to be Bob',
    categories: {
      create: [
        {
          assignedBy: 'Bob',
          assignedAt: new Date(),
          category: {
            connect: {
              id: 9,
            },
          },
        },
        {
          assignedBy: 'Bob',
          assignedAt: new Date(),
          category: {
            connect: {
              id: 22,
            },
          },
        },
      ],
    },
  },
})

That's what I did:

const assignCategories = await prisma.city.create({
    data: {
      name: 'Toronto',
      products: {
        create: [
          {
            product: {
              connect: {
                id: 1
              },
            },
          },
          {
            product: {
              connect: {
                id: 15
              },
            },
          },
          {
            product: {
              connect: {
                id: 11
              },
            },
          },
          {
            product: {
              connect: {
                id: 18
              },
            },
          },
        ],
      },
    },
  })

It's working good but is there any way to do it more succinctly? Do I really need to pass a new "big" object for each product i'm adding? I tried to pass the array of product id's to connect but it doesn't work.

CodePudding user response：

Yes you would need to pass it this way as you're using explicit many-to-many relations.

You can convert your schema to implicit many-to-many relations and that would make the create/connect syntax easier.