Composite Primary Key with relationMode Prisma and Foreign Key

[varugasu]

Bug description

I have a table with a composite primary key, and one of these keys is also a foreign key:

generator client {
    provider = "prisma-client-js"
}

datasource db {
    provider     = "mysql"
    url          = env("DATABASE_URL")
    relationMode = "prisma"
}

model Restaurant {
    id                   BigInt                 @id @default(autoincrement())
    RestaurantPageImages RestaurantPageImages[]

    @@index([externalId])
}

model RestaurantPageImages {
    restaurantId BigInt
    imageId      Int
    url          String
    Restaurant   Restaurant @relation(fields: [restaurantId], references: [id])

    @@id([restaurantId, imageId])
}

Yet, I still got the warning on the line Restaurant Restaurant @relation(fields: [restaurantId], references: [id]):

With `relationMode = "prisma"`, no foreign keys are used, so relation fields will not benefit from the index usually created by the relational database under the hood. This can lead to poor performance when querying these fields. We recommend adding an index manually. Learn more at https://pris.ly/d/relation-mode-prisma-indexes" 

However, this is misleading because we would not have performance issues since the restaurantId is used as a hash key on the composite key

How to reproduce

1. Have the Prisma VSCode plugin installed
2. Use the Prisma file above

Expected behavior

No warning is shown

Prisma information

Prisma 4.9.0

Environment & setup

• OS: Mac OS
• Editor: VSCode
• Editor version: 1.76.0
• Extension version:v4.11.0

[Druue]

Hey, I get the following error with the schema posted above, am I missing something?

[varugasu]

My bad, @Druue . I deleted some data to make it readable but left some garbage. You can remove the @@index([externalId]) to reproduce the warning:

generator client {
    provider = "prisma-client-js"
}

datasource db {
    provider     = "mysql"
    url          = env("DATABASE_URL")
    relationMode = "prisma"
}

model Restaurant {
    id                   BigInt                 @id @default(autoincrement())
    RestaurantPageImages RestaurantPageImages[]
}

model RestaurantPageImages {
    restaurantId BigInt
    imageId      Int
    url          String
    Restaurant   Restaurant @relation(fields: [restaurantId], references: [id])

    @@id([restaurantId, imageId])
}

[Druue]

Ah, yep!

[Vap0r1ze]

I also have this issue with this schema

generator client {
    provider = "prisma-client-js"
}

datasource db {
    provider     = "mysql"
    url          = env("DATABASE_URL")
    relationMode = "prisma"
}

model User {
    id        String   @id @default(uuid())
    name      String
    image     String
    createdAt DateTime @default(now())

    ownedLobbies Lobby[]
    playerships  Playership[]
    decks        Deck[]
}

model Playership {
    lobbyId String
    userId  String
    lobby   Lobby  @relation(fields: [lobbyId], references: [id], onDelete: Cascade)
    user    User   @relation(fields: [userId], references: [id], onDelete: Cascade)

    joinedAt    DateTime @default(now())
    permissions Int

    @@id([lobbyId, userId])
}

model Deck {
    name      String
    createdAt DateTime @default(now())

    owner   User   @relation(fields: [ownerId], references: [id], onDelete: Cascade)
    ownerId String

    @@id([ownerId, name])
}

model Lobby {
    id        String   @id
    createdAt DateTime @default(now())

    ownerId     String
    owner       User         @relation(fields: [ownerId], references: [id], onDelete: Cascade)
    playerships Playership[]

    @@index([ownerId])
}