2

2 つのクエリがあり、SQL のような結合を行いたい

たとえば、私はこれらのテーブルを持っています..

object Family extends Table[Long]("Family") {
  def id = column[Long]("id")
  def * = id
}

object Person extends Table[(Long, Long)]("Person") {
  def id = column[Long]("id")
  def FamilyId = column[Long]("FamilyId")
  def * = id ~ FamilyId ~ size
}
4

3 に答える 3

4 
val implicitInnerJoin = for {
  c <- Family
  s <- Person if c.id === s.FamilyId
} yield (c.id, s.id)
于 2013-09-02T11:21:17.600 に答える
1

Slick のドキュメントから: http://slick.typesafe.com/doc/1.0.0/lifted-embedding.html#joining-and-zipping、以下は Slick で可能な結合の一部とそれに関連する大まかな SQL です。

val implicitCrossJoin = for {
  c <- Coffees
  s <- Suppliers
} yield (c.name, s.name)

//SELECT c.name, s.name FROM Coffees c, Suppliers s


val implicitInnerJoin = for {
  c <- Coffees
  s <- Suppliers if c.supID === s.id
} yield (c.name, s.name)
//SELECT c.name, s.name FROM Coffees c, Suppliers s where c.supID = s.id    

val explicitCrossJoin = for {
  (c, s) <- Coffees innerJoin Suppliers
} yield (c.name, s.name)
//SELECT c.name, s.name FROM Coffees c CROSS JOIN Suppliers s    

val explicitInnerJoin = for {
  (c, s) <- Coffees innerJoin Suppliers on (_.supID === _.id)
} yield (c.name, s.name)
//SELECT c.name, s.name FROM Coffees c INNER JOIN Suppliers s ON (c.supID = s.id)   

val explicitLeftOuterJoin = for {
  (c, s) <- Coffees leftJoin Suppliers on (_.supID === _.id)
} yield (c.name, s.name.?)
//SELECT c.name, s.name FROM Coffees c LEFT OUTER JOIN Suppliers s ON (c.supID = s.id)

val explicitRightOuterJoin = for {
  (c, s) <- Coffees rightJoin Suppliers on (_.supID === _.id)
} yield (c.name.?, s.name)
//SELECT c.name, s.name FROM Coffees c RIGHT OUTER JOIN Suppliers s ON (c.supID = s.id)

val explicitFullOuterJoin = for {
  (c, s) <- Coffees outerJoin Suppliers on (_.supID === _.id)
} yield (c.name.?, s.name.?)
//SELECT c.name, s.name FROM Coffees c FULL OUTER JOIN Suppliers s ON (c.supID = s.id)

ご覧のとおり、ほとんどの構造は SQL に直接マップされます。

それが役立つことを願っています

于 2013-10-02T23:06:30.560 に答える