Parent-child query in 2.x

[Richard Rodseth]

I have a domain object represented by two tables with a 1 to many parent child relationship,

and wish to return a complete object containing the parent attributes and a list of the children. 

I found this question and Christopher's answer using groupBy:

http://grokbase.com/t/gg/scalaquery/142vt39evq/2-0-0-query-with-outer-join-returning-object-and-count-of-joined-rows

Are there any samples showing how to address this very common use case?

Thanks.

[Richard Rodseth]

Here's the example from that link:

def findParentAndNumberOfChildren(parentField: String)
   = parents.filter(_.parentField === parentField)
        .leftJoin(children).on(_.id === _.parentId)
        .filter{ case(parent,child) => /* your filters */ }
        .groupBy{ case(parent,_) => parent }
        .map{ case (parent,group) => (parent,group.size) }
        .firstOption

In my case I don't want the group list contents not its size, and would like to map the whole thing to a case class.

In a single table, I have the projection operator to do the case class mapping, but I'm unclear how to do it here.

The types are very confusing.

Any help appreciated.

[Richard Rodseth]

Any takers?