Question

Having trouble with AR 2.3.5, e.g.:

users = User.all( :select => "u.id, c.user_id", :from => "users u, connections c",
       :conditions => ... )

Returns, e.g.:

=> [#<User id: 1000>]
>> users.first.attributes
=> {"id"=>1000, "user_id"=>"1000"}

Note that AR returns the id of the model searched as numeric but the selected user_id of the joined model as a String, although both are int(11) in the database schema.

How could I better form this type of query to select columns of tables backing multiple models and retrieving their natural type rather than String ? Seems like AR is punting on this somewhere. How could I coerce the returned types at AR load time and not have to tack .to_i (etc.) onto every post-hoc access?

Answer 1

Why are you using :from => “users” inside a User.method ?
The following will do an inner join (which is what you are doing anyways)

users = User.all(:include => :connections, :select => "users.id, connections.user_id", :conditions => {...})

This is going to be very heavy query for the database.
Faster query would be with the outer join though.

This will also return the keys as INT not STRING

A much faster alternative was

Connection.all(:include => :user, :conditions => {...}).collect {|e| [e.user_id, e.id] }

This gives you an array of arrays with the ids. If you are going to select “id, user_id” columns only, then it may not necessarily be as AR object. An array can be faster.

I hope I am not missing some point here. Suggest me, if I am.