Named_scope issue undefined method that is a db column name


#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:inmethod_missing’
vendor/rails/activerecord/lib/active_record/named_scope.rb:171:in
send' vendor/rails/activerecord/lib/active_record/named_scope.rb:171:inmethod_missing’
vendor/rails/activerecord/lib/active_record/base.rb:2003:in
with_scope' (__DELEGATION__):2:insend
(DELEGATION):2:in with_scope' app/controllers/orders_controller.rb:23:inshow’

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

On May 7, 5:58 pm, erik removed_email_address@domain.invalid wrote:

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

On May 7, 10:04 am, Frederick C. removed_email_address@domain.invalid


#4

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