"undefined method"-error

Rails
1

Hi,

I’m new to rails and so far think it’s great, but I’m having some
major issues with a many-through relationship.

There are three tables:
reporttemplates
articlestemplates_reporttemplates (additional attribute “optional”)
articletemplates

They are connected to each other via has_many and through + belongs_to
in articlestemplates_reporttemplates.

Now, I need to display all articletemplates and show, if there is a
connection (entry in articlestemplates_reporttemplates) to the current
reporttemplate. So in the controller I call
@articletemplates = Articletemplate.find(:all, :joins=>"LEFT JOIN
articletemplates_reporttemplates ON
articletemplates_reporttemplates.articletemplate_id =
articletemplates.id WHERE
articletemplates_reporttemplates.reporttemplate_id = "+params[:id])

So far, everything is working. When I call
<% puts YAML::dump(articletemplate.articletemplates_reporttemplates)
%>
in the view, it gives me:

  • !ruby/object:ArticletemplatesReporttemplate
    attributes:
    created_at: 2008-12-16 17:24:19
    optional: “0”
    updated_at: 2008-12-16 17:24:19
    id: “1”
    reporttemplate_id: “1”
    articletemplate_id: “1”
    attributes_cache: {}

But when I try to access the attribute “optional”, I always get an
error message!
<% if articletemplate.articletemplates_reporttemplates.optional == 0
%>
leads to
“undefined method `optional’ for #Class:0x7f83e7451880”

Why does it tell me “undefined”, when one line above it tells me there
is an attribute “optional”?

Any help is appreciated!

Best Regards,
Daniel
Süpke

2

c’mon guys, don’t leave me hanging on my very first rails question
here ;).

It’s basically just: How can the debug output give tell me something
is an object with attributes and then it doesn’t let me access this
attributes? Maybe it’s a bug. Well, if no one has a clue I will try to
find a bug tracker and post it there, but it’s probably just my lack
of knowledge in ruby/rails.

Regards,
Daniel
Süpke

3

On 18 Dec 2008, at 16:22, Daniel Süpke wrote:

But when I try to access the attribute “optional”, I always get an
error message!
<% if articletemplate.articletemplates_reporttemplates.optional == 0
%>
leads to
“undefined method `optional’ for #Class:0x7f83e7451880”

Why does it tell me “undefined”, when one line above it tells me there
is an attribute “optional”?

Assuming you’re using the normal conventions,
articletemplates_reporttemplates is an array. it doesn’t have an
optional attribute (but the elements inside it do)

Fred

4

Thanks a bunch, that helped. Didn’t know that “—” is meant to
represent an array, YAML::dump could be more intuitive there. It only
told me “object”, so I never even thought of an array. Well, now it
works, so thanks again!