Rails - May 2009 - named_scope issue undefined method that is a db column name

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

On May 7, 5:58 pm, erik <e...-9T/GIyPsA//QT0dZR+AlfA@public.gmane.org>
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
> 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

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 Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> On May 7, 5:58 pm, erik
<e...-9T/GIyPsA//QT0dZR+AlfA@public.gmane.org> 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
>
> > 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
>
>

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


On May 7, 10:22 am, erik <e...-9T/GIyPsA//QT0dZR+AlfA@public.gmane.org>
wrote:
> 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 Cheung
<frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> wrote:
>
> > On May 7, 5:58 pm, erik
<e...-9T/GIyPsA//QT0dZR+AlfA@public.gmane.org> 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
>
> > > 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
>
>