+ # need to start the transaction here, so that the database can
+ # provide repeatable reads for the used-by checks. this means it
+ # shouldn't be possible to get race conditions.
+ Node.transaction do
+ check_consistency(self, new_node, user)
+ way = WayNode.find(:first, :joins => "INNER JOIN current_ways ON current_ways.id = current_way_nodes.id",
+ :conditions => [ "current_ways.visible = ? AND current_way_nodes.node_id = ?", true, self.id ])
+ raise OSM::APIPreconditionFailedError.new("Node #{self.id} is still used by way #{way.id}.") unless way.nil?
+
+ rel = RelationMember.find(:first, :joins => "INNER JOIN current_relations ON current_relations.id=current_relation_members.id",
+ :conditions => [ "visible = ? AND member_type='Node' and member_id=? ", true, self.id])
+ raise OSM::APIPreconditionFailedError.new("Node #{self.id} is still used by relation #{rel.relation.id}.") unless rel.nil?
+
+ self.changeset_id = new_node.changeset_id
+ self.visible = false
+
+ # update the changeset with the deleted position
+ changeset.update_bbox!(bbox)
+
+ save_with_history!