drop/prisma/schema/collection.prisma

model Collection {
    id   String @id @default(uuid())
    name String

    isDefault Boolean @default(false)
    userId    String
    user      User    @relation(fields: [userId], references: [id])

    entries CollectionEntry[]
}

model CollectionEntry {
    collectionId String
    collection   Collection @relation(fields: [collectionId], references: [id], onDelete: Cascade)

    gameId String
    game   Game   @relation(fields: [gameId], references: [id], onDelete: Cascade)

    @@id([collectionId, gameId])
}