What's the best practice of simple Slick INSERT/GET? - postgresql

Question

I need to use Slick 3.1.1 for a Postgres based project, but I have a hard time to write clean code for the following super simple usage:
Assume I have a Task model:
case class Task(id: Option[UUID], foo: Int, bar: String)
The id: UUID is the primary key, so I should NOT provide it (id = None) when doing database INSERT. However, I do need it when doing GET which maps a database row to a Task object.
Therefore, the Slick Table class becomes very ugly:
class Tasks(tag: Tag) extends Table[Task](tag, "tasks") {
def id = column[UUID]("id", O.SqlType("UUID"), O.PrimaryKey)
def foo = column[Int]("foo")
def bar = column[String]("bar")
def insert: MappedProjection[Task, (Int, String)] =
(foo, bar).shaped.<>(
{ tuple =>
Task.tupled(None, tuple._1, tuple._2)
}, { (task: Task) =>
Task.unapply(task).map { tuple =>
(tuple._2, tuple._3)
}
}
)
override def * : ProvenShape[Task] =
(id.?,
foo,
bar).shaped.<>(Task.tupled, Task.unapply)
}
If case class Task has 10 elements, I then have to write (tuple._1, tuple._2, tuple._3, ......) My co-workers will slap my face if I submit a PR like above. Please suggest!

Answer 1

If you'll let the database to autoincrement your IDs, that Table definition could be shortened significantly:
import slick.driver.PostgresDriver.api._
import java.util.UUID
case class Task(id: Option[UUID], foo: Int, bar: String)
class Tasks(tag: Tag) extends Table[Task](tag, "tasks") {
def id = column[Option[UUID]]("id", O.SqlType("UUID"), O.PrimaryKey, O.AutoInc)
def foo = column[Int]("foo")
def bar = column[String]("bar")
def * = (id, foo, bar) <> (Task.tupled, Task.unapply)
}
This could be improved further by moving the id field to the end of the case class and giving it the default None value. This way you won't have to provide it every time you want to instantiate the Task:
case class Task(foo: Int, bar: String, id: Option[UUID] = None)
val firstTask = Task(123, "John")
val secondTask = Task(456, "Paul")