Klasu

// Simple monad to deal with multiple database transactions with same connection, their commits and rollbacks
// Something similar done in http://advorkovyy.blogspot.com.au/2010/10/transactional-monad-for-scala.html
 
import java.sql.Connection
 
trait DbTransaction[A] {
  def unit: Connection => A
  def map[B](f: A => B): DbTransaction[B] = DbTransaction {
    connection => f(unit(connection))
  }

Klasu

import org.specs2.mutable.Specification

case class A(id: Int, created: String)
case class B(id: Int, aId: Int)
case class C(id: Int, created: String)

object ACreator {
  val a = A(
    id = 1,
    created = "A"