问题
In my rails application i am writing mongo db query to collections where it should perform AND operation (Example: Basically i want all the user details from collection where city=delhi and gender=male).I am stuck in this , I am referring to this link . http://mongomapper.com/documentation/plugins/querying.html. Even i have followed the below links MongoMapper OR clause on 2 columns - Rails 3.1.rc4. But nothing is working, I am new to this i dont know is this correct approach or else is there any methods, kindly help me out in this.
I am using rails 3.1 and mongo_mapper ORM.
query details :
@c=Customer.where(:$and => [:gender => "Male",:city => "DELHI/NCR"])
Output: #<Plucky::Query $and: [{:gender=>"Male", :city=>"DELHI/NCR"}], transformer: #<Proc:0xe6429b4@/home/vijay/.rvm/gems/ruby-1.9.2-p290/gems/mongo_mapper-0.11.0/lib/mongo_mapper/plugins/querying.rb:79 (lambda)>>
I have tried this also nothing is working
@c=Customer.where(:$and => [{:gender => "Male"},{:city => "DELHI/NCR"}])
回答1:
as you use it it would only create the query, you will need to 'execute' it by appending .all
@customers = Customer.where(:gender => "Male", :city => "DELHI/NCR").all
read more on it here: http://mongomapper.com/documentation/plugins/querying.html#criteria
回答2:
@c = Customer.where(:gender => "Male",:city => "DELHI/NCR").all
回答3:
Notice you don't need both the where and all.
You can simply write:
@customers = Customer.all(:gender => "Male", :city => "DELHI/NCR")
来源：https://stackoverflow.com/questions/9110385/query-is-not-executing-in-rails-app-using-mongomapper