E.g. if I use something like

@@id([a, b])

, how can I do upserts on those models?

Yes, you can do that, see https://www.prisma.io/docs/reference/tools-and-interfaces/prisma-client/crud#upsert

Ah, nice, let me have a look 🙂

Something like this:

await prisma.user.upsert({
    where: {
      name_email: {
        name: 'name',
        email: 'email',
      },
    },
    create: {
      email: 'email',
      name: 'name',
    },
    update: {
      age: 21,
    },
  })

Given this schema:

model User {
  name  String
  email String
  age   Int?
  @@id([name, email])
}

Nice, will try. My typings are not suggesting a_b is valid on where.

Maybe restart your editor or generate Prisma again?

Hah, yeah, it was the former. I hate when this happens 😄 #vscode