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copied!<p>If each News, Event, etc. will belong to only 1 Region, tags don't seem the most natural fit IMO. This leaves you with 2 options:</p> <p><strong>Add a region_id field to each model</strong></p> <p>This is simplest, but has the drawback that you will <em>not</em> be able to look at all the "regioned" items at once - you'll have to query the news, events, etc. tables separately (or use a UNION, which ActiveRecord doesn't support).</p> <p><strong>Use RegionLink model with polymorphic associations</strong></p> <p>This is only slightly more complicated, and is in fact similar to how acts_as_taggable_on works. Look at the Rails docs on *belongs_to* for a fuller description of polymorphic relationships if you are unfamiliar</p> <pre><code>class Region < ActiveRecord::Base has_many :region_links has_many :things, :through => :region_links end # This table with have region_id, thing_id and thing_type class RegionLink < ActiveRecord::Base belongs_to :region belongs_to :thing, :polymorphic => true end class Event < ActiveRecord::Base has_one :region_link, :as => :thing has_one :region, :through => :region_link end # Get all "things" (Events, Projects, etc.) from Region #1 things = Region.find(1).things </code></pre> <p>Renaming is quite simple - just rename the Region. Deleting/reassigning regions is also simple - just delete the RegionLink record, or replace it's region_id.</p> <p>If you find yourself duplicating a lot of region-related code in your Event, etc. models, you may want to put it into a module in lib or app/models:</p> <pre><code>module Regioned def self.inluded(base) base.class_eval do has_one :region_link, :as => :thing has_one :region, :through => :region_link ... end end end class Event < ActiveRecord::Base include Regioned end class Project < ActiveRecord::Base include Regioned end </code></pre>

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