Google App Engine - Python appication: find relationship among nodes

I have following model:

class Relations(db.Model):
    name = db.StringProperty()
    events = db.StringListProperty(required = True)

and following Relations data:

name = direct  events = [node_A,event_B],
name = inverse events = [node_A,node_G],
name = direct  events = [node_A,node_H],
name = inverse events = [node_A,node_X],
name = direct  events = [node_A,node_Y]

and based on user input (e.g node_A up) I need开发者_如何学Python to find the relationship among nodes and output the nodes as follows:

output: node_B - up, node_G - down, node_H - up, node_X - down, node_Y - up

In other words I need queries to find out relationship among nodes for example, if relationship of node_A to node_B is direct and node_A to node_X is inverse output will be node_B - up and node_X - down as in the output example above.

If user input will be node_G down then output required is node_A down since there are no other nodes related to node_G except node_A.

Please suggest the queries. Thanks in advance Prakash

If I understand correctly, something like this could work:

query = Relations.all()
query.filter('events =', node)

direct_list = []
inverse_list = []

for relation in query:
  relation.events.remove(node)
  if relation.name == 'direct':
    direct_list.extend(relation.events)
  else:
    inverse_list.extend(relation.events)

if action == 'up':
  #direct_list is all 'up'
  #inverse_list is all 'down'
else:
  #opposite of above