How do you check if an embedded document exists in a document in mongoid?

Question

How do you check if an embedded document exists for a document using mongoid in Ruby on Rails? Let's say I have a user document that has name , email and can have an embedded nicknames document. Right now, if I run user.first.nicknames , and if this user does not have an embedded nicknames document, it will fail. Have I tried matches? and exists? but they do not work.

Thanks!

Answer 1

Should this return true if it does not exist User.first.nicknames.nil? and this will return true if it exists: User.first.nicknames.present?

Answer 2

With a little help from the other answers here, I found something that worked for me, and I think this is what the original poster had in mind;

 Model.where(:"subdoc.some_attribute".exists => true) 

This will return all documents where "some_attribute" exists in the subdocument. Pay attention to the syntax of the character, to what I was missing.

Answer 3

You can do User.where(:nicknames.exists => true).include?(user) .

User.where(:nicknames.exists => true) will only return documents containing nicknames .

Answer 4

should be as simple as {"user":{"$exists":"nicknames"}}