named_scope issue undefined method that is a db column name

rubyonrails-talk
1

I'm new to named_scope so bear with me if this is dumb.

I have created two named scopes both using lambda to pass in arguments. One passes in a single argument and works great the other passes in two arguments and doesn't work and gives me this error:

undefined method `last_reference' for #<Class:0x4464cb4>

vendor/rails/activerecord/lib/active_record/base.rb:1833:in `method_missing_without_paginate' /opt/ruby-enterprise-1.8.6-20090201/lib/ruby/gems/1.8/gems/mislav- will_paginate-2.3.8/lib/will_paginate/finder.rb:170:in `method_missing' vendor/rails/activerecord/lib/active_record/named_scope.rb:171:in `send' vendor/rails/activerecord/lib/active_record/named_scope.rb:171:in `method_missing' vendor/rails/activerecord/lib/active_record/base.rb:2003:in `with_scope' (__DELEGATION__):2:in `__send__' (__DELEGATION__):2:in `with_scope' app/controllers/orders_controller.rb:23:in `show'

The two named_scopes: class OrderTrack < ActiveRecord::Base     named_scope :one, lambda {|id,account_id| {:conditions => ["id = ? and account_id = ?",id,account_id]}}     named_scope :all, lambda {|account_id| {:conditions => ["account_id = ?",account_id]}} end

I believe I need to use lambda to pass in arguments. The named_scope :all works great and ends up doing an sql query like: SELECT * FROM `order_tracks` WHERE (account_id = 344)

But the single one that I want to end up doing something like: SELECT * FROM `order_tracks` WHERE (id = 3 and account_id = 344) doesn't want to work.

This is soft of a contrived example, but I'm just trying to see if I understand this stuff. Thanks. Erik

2

I'm new to named_scope so bear with me if this is dumb.

I have created two named scopes both using lambda to pass in arguments. One passes in a single argument and works great the other passes in two arguments and doesn't work and gives me this error:

I'm going to make a wild guess that this is because you're assuming that OrderTrack.one(...) is a single object rather than an array (possibly containing only one row)

Fred

3

Yeah, that's right. I thought it was dying before sending the sql query, but i was reading my exception incorrectly. I didn't believe it was an array because I had seen no_method 'blah' for <Array:...> before, but it through me off as it said Class.

So here's another dumb question... I can put [0] at the end of my OrderTrack.one....[0] line, but is there a way to make named_scope only return a single object of the activerecord type as opposed to an array? Thanks. Erik

4

Reading is sometimes magic... OrderTrack.one(....).first does the trick. Erik