CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-3mongoidmongoid3
ere
ere

Reputation: 1779

mongoid where with has_many relation

I have 3 models

City.rb

has_many :places

Place.rb

has_many :reviews, as: :reviewable

And Reviews which have an attribute state which I would like to be able to check.

Review.rb

  belongs_to :reviewable, polymorphic: true
  state_machine :initial => :draft do #etc.

I would like to be able to call City.find("somecity").places

and instead of showing all places, replace the default scope to find only places which have a review with the state of "published"

In activerecord something like... 

City.find("somecity").places.where('reviews.state' => 'published')

Is there any way to do this in mongoid or my second option would be to incorporate a new attribute into places which gets set to active whenever a review is published.

Upvotes: 2

Views: 1029

Answers (1)

holden
holden

Reputation: 13591

If you find yourself having problems with joins, you should probably think about de-normalizing your data. Basically just replicating data in two places, this is not considered good in the SQL universe but with No-SQL it handles cases where you might normally perform a join. Increasing Speed, but using more space.

For that you have two great gems in mongoid:

https://github.com/dzello/mongoid_alize

See blog post for info on demormalizing: http://blog.joshdzielak.com/blog/2012/05/03/releasing-mongoid-alize-comprehensive-field-denormalization-for-mongoid/

or https://github.com/logandk/mongoid_denormalize

Although my preference is for the former.

Upvotes: 4

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