I'm following the Slick documentation example for autoincrementing fields and I'm having trouble creating a mapped projection that ... well, only has one column.
case class UserRole(id: Option[Int], role: String)
object UserRoles extends Table[UserRole]("userRole") {
def id = column[Int]("ID", O.PrimaryKey, O.AutoInc)
def role = column[String]("ROLE")
// ...
def * = id.? ~ role <> (UserRole, UserRole.unapply _)
// NEXT LINE ERRORS OUT
def forInsert = role <> ({t => UserRole(None, t._1)}, {(r: UserRole) => Some((r.role))}) returning id
}
The error is "value <> is not a member of scala.slick.lifted.Column[String]"
I also thought it'd be more efficient to design my schema like so:
case class UserRole(role: String)
object UserRoles extends Table[UserRole]("userRole") {
def role = column[Int]("ROLE", O.PrimaryKey)
// ...
def * = role <> (UserRole, UserRole.unapply _)
}
But then I start getting the same error as above, too. "value <> is not a member of scala.slick.lifted.Column[String]"
What am I really doing? Do I just not have a projection anymore because I only have one column? If so, what should I be doing?
This is a known issue with Slick; mapped projections do not work with a single column. See https://github.com/slick/slick/issues/40
Luckily, you don't need a mapped projection for your code to work. Just omit everything after and including the <>
. See scala slick method I can not understand so far for a great explanation of projections. It includes the information you need to get going.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With