How to store array in attribute of ActiveRecord model?

Question

I have model waypoint with two attributes

1. coordinates
2. geocode_text

And model route that is no more than sorted array of waypoints with some additional text info. Some routes can have same waypoints, so I want to separate waypoints from routes.

What is the best way to store waypoints inside route?

I see several ways:

• serialize waypoints ids to waypoint_ids attribute of route, but in such situation I will not be able to get route and all his waypoints in one SQL request, because waypoint ids will be hidden in serialized string.

• create some third model that have such arguments

  1. route_id
  2. waypoint_id
  3. position

  Connect routes and waypoints with many-to-many association and store position of waypoint in route in position attribute. But it seems to be over-complicated.

What is the best way for me in such situation?

Answer 1

I'd opt for the second option -- use a join table (RouteWaypoints) with something like acts_as_list so that you can retrieve the Route with all it's Waypoints correctly sorted. This isn't overkill -- the DB is really good at this stuff.