Combining postgres_ext (or Rails 4) arrays with associations

Question

I'm trying to develop a many-to-many relationship between tags (in the tags table) and items (in the items table) using a field of type integer[] on each item.

I know that Rails 4 (and Rails 3 via postgres_ext) has support for Postgres' arrays feature through the :array => true parameter, but I can't figure out how to combine them with Active Record associations.

Does has_many have an option for this? Is there a gem for this? Should I give up and just create a has_many :through relationship (though with the amount of relations I'm expecting this is probably unmanageable)?

Answer 1

All you really need to do is

def tags
  Tag.where(id: tag_ids)
end

def add_tag(tag)
  self.tag_ids += [tag.id] unless tag_ids.include?(tag.id)
end

At least that's what I do at the moment. I do some pretty cool stuff with hashes (hstore) as well with permissions. One way of handling tags is to create the has_many through and persist the tags in a string array column as they are added for convenience and performance (not having to query the 2 related tables just to get the names out). I you don't necessarily have to use active record to do cool stuff with the database.