Question

I am using mongo db for a model in my rails application, and when I execute

Model.where(:$or => [{:field1 => true}, {:field2 => true}])

produces plucky query

#<Plucky::Query $or: [{:field1=>true}, {:field2=>true}], transformer: #<Proc:0xa4b1c5c@/home/x/.rvm/gems/ruby-1.9.2-p290@app/gems/mongo_mapper-0.9.2/lib/mongo_mapper/plugins/querying.rb:79 (lambda)>>

performs OR operation and fetches the correct results, ie, field1 or field2 is true but

Model.where(:$and => [{:field1 => true}, {:field2 => true}])

produces plucky query

#<Plucky::Query $and: {"$in"=>[{:field1=>true}, {:field2=>true}]}, transformer: #<Proc:0xa435120@/home/x/.rvm/gems/ruby-1.9.2-p290@app/gems/mongo_mapper-0.9.2/lib/mongo_mapper/plugins/querying.rb:79 (lambda)>>

doesn’t perform the AND operation, instead it throws error

Mongo::OperationFailure Exception: $and expression must be a nonempty
array

DETAILS

Rails version: 3.1,
Mongo version: 2.0.0,
mongo_mapper gem version: 0.9.2

Answer 1

You will need to upgrade MongoMapper. $and support was added in plucky 0.4.x, which MongoMapper uses as of version 0.10.1.

This commit added $and support to plucky and is part of plucky 0.4.2 and greater.

This commit updated MongoMapper to use plucky 0.4.x and is part of MM 0.10.1 and greater.