mapping a column in model to another model

model Session {
    id           String   @id @default(cuid())
    sessi onToken String   @unique
    userId       String
    expires      DateTime
    user         User     @relation(fields: [userId], references: [id], onDelete: Cascade)
}

model User {
    id            String    @id @default(cuid())
    name          String?   
    email         String?   @unique
    emailVerified DateTime?
    image         String?
    accounts      Account[]
    sessions      Session[]
    comments      Comment[]
}

model VerificationToken {
    identifier String
    token      String   @unique
    expires    DateTime

    @@unique([identifier, token])
}

model Comment {
    id         String     @id @default(cuid())
    createdAt  DateTime   @default(now())
    updatedAt  DateTime   @updatedAt
    userId     String
    content    String     @db.Text
    user       User       @relation(fields: [userId], references: [id])

}

model Comment {
    id         String     @id @default(cuid())
    createdAt  DateTime   @default(now())
    updatedAt  DateTime   @updatedAt
    userId     String
    userName   String
    content    String     @db.Text
    user       User       @relation(fields: [userId, userName], references: [id, name])
}