Getting autoincrement values with Slick library in Scala
Question
How do I get the auto-incremented values for records inserted with Slick? The following code prints 1111. I would have expected it to print 1234
import scala.slick.driver.H2Driver.simple._
object TestMappedTable extends App{
case class User(id: Option[Int], first: String, last: String)
object Users extends Table[User]("users") {
def id = column[Int]("id", O.PrimaryKey, O.AutoInc)
def first = column[String]("first")
def last = column[String]("last")
def * = id.? ~ first ~ last <> (User, User.unapply _)
}
implicit val session = Database.forURL("jdbc:h2:mem:test1", driver = "org.h2.Driver").createSession()
session.withTransaction{
Users.ddl.create
print(Users.insert(User(None, "Jack", "Green" )))
print(Users.insert(User(None, "Joe", "Blue" )))
print(Users.insert(User(None, "John", "Purple" )))
print(Users.insert(User(None, "Jim", "Yellow" )))
}
}
I'm using Slick 0.11.2 for Scala 2.10.0-RC1
Solution
You can retrieve the generated value like this.
Add autoInc
method to Users
object.
def autoInc = id.? ~ first ~ last <> (User, User.unapply _) returning id
Use Users.autoInc.insert
instead.
print(Users.autoInc.insert(User(None, "Jack", "Green" )))
See also:
https://github.com/slick/slick/issues/10
https://github.com/slick/slick/commit/09a65a8e88a0363412e218dc5c06023b69809649
OTHER TIPS
The latest version of Slick (2.1.0) automatically takes care of ignoring the auto-incremented ids and the documentation demonstrates how to retrieve the id:
val userWithId =
(users returning users.map(_.id)
into ((user,id) => user.copy(id=Some(id)))
) += User(None, "Stefan", "Zeiger")
This is the full monty, where the retrieved value is then inserted back into the object you are adding to the table. If you just want to get your hands on the id itself:
val userId =
(users returning users.map(_.id)) += User(None, "Stefan", "Zeiger")
Both code snippets were taken from the official docs. It seemed like this question needed updating for newcomers (like me) who have never used earlier versions of Slick.
According to SLICK Inserting document, you should define a method forInsert
looks like:
def forInsert = first ~ last <> (
{ t =>
User(None, t._1, t._2)},
{ (u: User) =>
Some((u.first, u.last))
}) returning id
To get result:
def save(user: User): User = {
val id = users.forInsert.insert(user)
new User(Some(id), user.first, user.last)
}
For me, following source worked (Slick 3.0.2)
class Track(tag: Tag)
extends Table[(Int, String, String)](tag, "TRACK") {
// This is the primary key column:
def id: Rep[Int] = column[Int]("ID", O.PrimaryKey, O.AutoInc)
def artist: Rep[String] = column[String]("ARTIST")
def name: Rep[String] = column[String]("NAME")
def * : ProvenShape[(Int, String, String)] =
(id, artist, name)
}