Why custom ID for user in DB?

[rwieruch]

What's currently expected (example with Prisma):

// schema
model User {
  id           String    @id
  username     String    @unique
  email        String    @unique
  passwordHash String
  sessions     Session[]
}

// sign up
const userId = generateIdFromEntropySize(10);

await db.table("user").insert({
  id: userId,
  username: username,
  password_hash: passwordHash
});

const session = await lucia.createSession(userId, {});

Why not the following?

// user with default ID in schema
model User {
  id           String    @id @default(cuid())
  username     String    @unique
  email        String    @unique
  passwordHash String
  sessions     Session[]
}

// sign up
// const userId = generateIdFromEntropySize(10); <--- remove

const user = await db.table("user").insert({
  username: username,
  password_hash: passwordHash
});

const session = await lucia.createSession(user.id, {});

---

Why do we need to generate the userId ourselves? Wouldn't be it be one less step, and therefore even simpler for the developer and less error prone, to just let the internals of the ORM generate the ID? Is there any reason for using the extra step to create a custom userId with generateIdFromEntropySize? Thanks :)

[pilcrowOnPaper]

You're free to do whatever you want in regards to user creation :D The docs just show one way of doing it.

(One reason you might want to generate IDs yourself is that your DB engine might not be using a secure RNG, which may or may not be ideal)

[rwieruch]

Thanks for the clarification @pilcrowOnPaper 💯