মতভাবে relation — explicit N:M, self-relation

model Order {
  id       Int         @id @default(autoincrement())
  cells    OrderItem[]
}

model Product {
  id       Int         @id @default(autoincrement())
  lines    OrderItem[]
}

model OrderItem {
  order     Order   @relation(fields: [orderId], references: [id], onDelete: Cascade)
  orderId   Int
  product   Product @relation(fields: [productId], references: [id])
  productId Int
  qty       Int
  price     Decimal @db.Decimal(10, 2)

  @@id([orderId, productId])
}

model Employee {
  id        Int        @id @default(autoincrement())
  name      String
  manager   Employee?  @relation("ReportsTo", fields: [managerId], references: [id])
  managerId Int?
  reports   Employee[] @relation("ReportsTo")
}