I have a feeling I am gonna get my ass kicked here, but this is my first attempt at creating real life model logic I have 3 models: Trader - https://github.com/JonleePeakman/locations/blob/master/app/models/trader.rb Service - https://github.com/JonleePeakman/locations/blob/master/app/models/service.rb Location - https://github.com/JonleePeakman/locations/blob/master/app/models/location.rb and my DB Schema is: https://github.com/JonleePeakman/locations/blob/master/db/schema.rb This is all I have at the moment and it does exactly what I want it to do. I will plan on my controller and views later but I want to pause and review on my work and could use some help as I am unsure if I am overusing callbacks especially in the Service model and what I could do otherwise. A quick overview of the plan is: A Trader has and belongs to many Locations and vice-versa, and a Trader has many Services each of which have a range. This range is the distance a trader may travel to provide the service from their central post_code e.g. a builder might travel 20 miles to build a porch but would travel 50 miles for a customer to build a full house extension. Therefore the Locations for a Trader all hinge on the maximum range of their Services. The Locations table is populated with UK postcode data with Lat/Lon coordinates and all distances and ranges are calculated using the Haversine formula. The plan is when a User visits the website they enter their post code, firstly all Traders in the Location will be identified. Then When the user clicks on a specific Trader, the Trader=>'services_in' function will be called to only show the services that the trader provides within their post code. I hope that makes sense and you have a little time to peruse the models, I could really do with having a discussion on what I have created so far to see how smelly my code is. As I say I have never done anything to this level before. much regards JL -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/e0bf5450-d8f9-4e2e-b484-994c3ec8022c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.