class Owner {
   static hasOne = [ owned:Owned ]
}

class Owned {
  Owner owner
}

class OwnedController {
  def save = {
    def owner = Owner.findById(1)
    owner.owned = new Owned()
    owner.save()
    redirect(controller:"owner", action:"view")
  }
}

class OwnerController {
  def view = {
    [owner:Owner.findById(1)]
  }
}

//owner/view.gsp
owned exists: ${owner.owned != null}

//outputs owned exsits: false consistantly