Joining multiple tables while accumulating conditions

Question

I have a class method Relationship.with_attributes that I use to build up a complex scope based on multiple input parameters to return Relationship objects associated with products that match certain attributes. In most cases, the information I match against is on the Product model and all is well:

def self.with_attributes(attributes)
  if (attributes.nil?)
    scoped
  else # (attributes.class == Hash)
    conds = joins(:product)

    attributes.each do |key, value|
      case key
      when "Category"
        # FIXME This doesn't work yet
        category = Category.find(value)
        categories = [category] + category.descendants
        categories.each { |c| conds.push(["categories.id = #{c.id}"], :or) }
      else
        conds.where(key => value)
      end
    end
  end
  conds
end

The challenge is I haven't been able to determine how to join in the Categorizations model when my attribute is a category. Any advice is much appreciated. Abbreviated models are below.

class Relationship < ActiveRecord::Base
  belongs_to :product
  …
end

class Product < ActiveRecord::Base
  has_many :relations
  has_many :categorizations
  …
end

class Categorizations < ActiveRecord::Base
  belongs_to :product
  …
end

score 2 · Accepted Answer · answered Sep 14 '12 at 20:47

2

I stumbled upon the answer soon after posting. The answer was to update conds = joins(:product) to:

conds = joins(:product, { :product => :categorizations })

answered Sep 14 '12 at 20:47

jredburn

798
5
9

Joining multiple tables while accumulating conditions

1 Answers1