title: Automatically add UUID relation on prisma create
body: <p>I have a <code>User</code>, <code>UserProfile</code> and <code>Post</code> model in my Postgres database. The <code>User</code> and <code>UserProfile</code> depend on each other. I am trying to create a <code>User</code> that automatically creates a <code>UserProfile</code> with it, but I can't seem to find out how to automatically assume the <code>User</code>'s ID for the <code>UserProfile</code> relation, I am using UUID for the <code>User</code> model.</p>
  <p><strong>Schema Models</strong></p>
  <pre class="lang-js prettyprint-override"><code>model User {
    id             String       @id @default(uuid())
    createdAt      DateTime     @default(now())
    username       String       @unique @db.VarChar(20)
    emailEncrypted String       @unique
    emailIv        String       @unique
    password       String
    isMod          Boolean      @default(false)
    isAdmin        Boolean      @default(false)
    emailConfirmed Boolean      @default(false)
    profile        UserProfile?
  }
  
  model UserProfile {
    user     User      @relation(fields: [id], references: [id])
    id       String    @unique
    posts    Post[]
    comments Comment[]
  }
  
  model Post {
    id        String      @id @default(uuid())
    createdAt DateTime    @default(now())
    title     String      @db.VarChar(300)
    caption   String      @db.VarChar(1000)
    upvotes   Int         @default(0)
    downvotes Int         @default(0)
    comments  Comment[]
    author    UserProfile @relation(fields: [authorId], references: [id])
    authorId  String
  }
  </code></pre>
  <p><strong>Query</strong></p>
  <pre class="lang-js prettyprint-override"><code>const user = await prisma.user.create({
      data: {
          username,
          emailEncrypted: encrypted,
          emailIv: iv,
          password: hashedPassword,
          profile: {
              create: {}, // create a UserProfile that assumes the created user's UUID as a relation
          },
      },
      select: {
          id: true,
      },
  });
  </code></pre>
  <p>As you can see, I have tried to use <code>create: {}</code> in order to assume the user's UUID, but it fails to create an actual <code>UserProfile</code>, just a <code>User</code>, which of course breaks the system.</p>