@default(autoincrement()) not working on non id integer fields

I am having an id field in my model that is not primary but I want it to be a autoincrement field. So, for this, I just added @default(autoincrement()) in the front of my id field. But this is not working id is not autoincrementing and even I am not able to create if I did not explicitly pass the id filed. This is my model.

model Mail {
    id Int   @default(autoincrement())
    createdAt  DateTime   @default(now())
    updatedAt  DateTime   @updatedAt
    body String
    to String
    from String
    subject String
    messageId String @id
    date DateTime
    attachments Attachment[]
}

[do4gr]

As per the linked investigation issue (https://github.com/prisma/prisma-engines/issues/903), this would work on Postgres and MySQL but would not work on SQLite. On MySQL the auto_increment column would also need to have an index defined.

We need to decide whether we should allow this if a supporting db is specified.

[tomhoule]

Linking corresponding engines issue: https://github.com/prisma/prisma-engines/issues/903