CODEWITHSUNDEEP
scalascala-2.10slick
expert
expert

Reputation: 30115

Inner join doesn't work in Slick

Could you please tell me why I'm not getting inner join I'm expecting to get ?

I have following tables

case class Ability(id: UUID, can: Boolean, verb: String, subject: String, context: String)

object Abilities extends Table[Ability]("abilities"){
  def id = column[UUID]("id", O.PrimaryKey)
  def can = column[Boolean]("is_can")
  def verb = column[String]("verb")
  def subject = column[String]("subject")
  def context = column[String]("context")

  def * = id ~ can ~ verb ~ subject ~ context <> (Ability, Ability.unapply _)
}

case class Role(id: UUID, name : String)

object Roles extends Table[Role]("roles"){
  def id = column[UUID]("id", O.PrimaryKey)
  def name = column[String]("name")

  def * = id ~ name <> (Role, Role.unapply _)
}

// And join table
case class AbilityRelationship(owner_id: UUID, obj_id: UUID, is_role: Boolean)

object AbilitiesMapping extends Table[AbilityRelationship]("abilities_mapping"){
  def owner_id = column[UUID]("owner_id")
  def obj_id = column[UUID]("obj_id")
  def is_role = column[Boolean]("is_role")

  def * = owner_id ~ obj_id ~ is_role <> (AbilityRelationship, AbilityRelationship.unapply _)
}

What I'm willing to do is to fetch list of Ability objects for particular owner (whether user or role). So following documentation I wrote following join query for it

val some_id = role.id
val q2 = for {
  a <- Abilities
  rel <- AbilitiesMapping
  if rel.owner_id === some_id.bind
} yield (a)

But q2.selectStatement returns absolutely wrong query for it. Which is select x2."id", x2."is_can", x2."verb", x2."subject", x2."context" from "abilities" x2, "abilities_mapping" x3 where x3."owner_id" = ? in my case.

How should it be implemented?

Thanks.

Upvotes: 0

Views: 2841

Answers (3)

critium
critium

Reputation: 652

Tried doing this as a comment to ruslan's answer, but I just dont have enough jedi powers:

Can you try if this desugar-ed version works?

val rightSide = AbilitiesMapping.filter(_.owner_id === some_id)    
val innerJoin = (Abilities innerJoin (rightSide) on (
  (l,r) => (l.id === r.obj_id)
).map { case (l, r) => l }

Upvotes: 1

pedrofurla
pedrofurla

Reputation: 12783

Try something like:

val q2 = for {
  a <- Abilities
  rel <- AbilitiesMapping
  if a.id == rel.obj_id && rel.owner_id === some_id.bind
} yield (a)

BTW, you know you can annotate your foreign keys in the Table objects right?

Upvotes: 2

expert
expert

Reputation: 30115

Well, after multiple attempts I made it

  val innerJoin = for {
    (a, rel) <- Abilities innerJoin AbilitiesMapping on (_.id === _.obj_id) if rel.owner_id === some_id.bind
  } yield a

But man... typesafe's documentation is really really weak for newcomers.

Upvotes: 10

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