You have a nil object

Rails
1

Hi People
I have just started using rails and am running into a few problems,

the basic setup I have is two tables, one called weburls and the other
called jobs, and the relationship between them is one weburl can have
many jobs, a job cant belong to multiple weburls

in the models I have (and im abit confused if they should be plural or
not)

class Job < ActiveRecord::Base
belongs_to:weburls
end

and

class Weburl < ActiveRecord::Base
has_many:Jobs
end

I have a list of websites so that when you click on show it will take
you to a page with a list of the jobs that are attached to it. the
parameter is passed in the url like this

redirect_to :controller =>‘jobs’, :action => ‘list’, :weburls_id =>
params[:id]

then in the def list in the jobs_controller.rb I have

def list
@job_pages, @job = Job.find(:all, :conditions =>[“weburls_id = ?”,
(params[:weburls_id]])
end

however the end result is You have a nil object when you didn’t expect
it!
You might have expected an instance of Array. The error occurred while
evaluating nil.each

Any help would be appreciated.

Cheers

simon

2

On 24 Apr 2008, at 12:57, Simon H. wrote:

class Weburl < ActiveRecord::Base
has_many:Jobs
end

It’s a plural if the association can have many objects. So belongs_to
and has_one are always singular, has_many is always plural

def list
@job_pages, @job = Job.find(:all, :conditions =>[“weburls_id = ?”,
(params[:weburls_id]])
end

That should be just

@jobs = Job.find(:all, :conditions =>[“weburls_id = ?”,
params[:weburls_id]])

(unless you wanted the paginate the results, in which case you’ll need
to use the classic_pagination or will_paginate plugins. I’d get things
working without first)

Fred

3

@jobs = Job.find(:all, :conditions =>[“weburls_id = ?”,
params[:weburls_id]])

Hi Fred thanks for your help.

I have changed it to this can corrected the models, however im still
getting the same error message. should the “@jobs” be just “@job” to
match the others in the def list. I changed it quickly to see but with
both variations it still comes up with the same error

the code snippet it gives is:

Extracted source (around line #10):

7: <% end %>
8:
9:
10: <% for job in @jobs %>
11:


12: <% for column in Job.content_columns %>
13: <%=h job.send(column.name) %>

hope this could be any help

Simon.

4

7: <% end %>
8:
9:
10: <% for job in @jobs %>
11:


12: <% for column in Job.content_columns %>
13: <%=h job.send(column.name) %>

sorry that was the error for when it was @job, this is the one for @jobs

5

On 24 Apr 2008, at 13:22, Simon H. wrote:

match the others in the def list. I changed it quickly to see but with
both variations it still comes up with the same error

If you’re using @jobs in your view then you need to be setting @jobs
somewhere in your controller.

Fred

6

19: <% end %>
20:
21:
22: <%= link_to ‘Previous page’, { :page => @job_pages.current.previous
} if @job_pages.current.previous %>
23: <%= link_to ‘Next page’, { :page => @job_pages.current.next } if
@job_pages.current.next %>
24:
25:

7

On 24 Apr 2008, at 13:37, Simon H. wrote:

sorry that was the error for when it was @job, this is the one for
@jobs
I think it would help if you detailed the changes you’ve made, right
know we know you’ve change some things but we don’t actually know what
you’ve ended up with.

Fred

8

Simon,

One of the points of model associations is that you get association
functionality.

Change your @jobs call to be:

@jobs = Weburl.find(params[:weburl_id]).jobs

(or if the parameter is “weburls_id” use that, although it should be
singular if you are dealing with a single weburl)

The above line finds the weburl with the ID then uses the has_many
association to get the jobs for that weburl.

Otherwise, the view code looks fine. Looks like standard scaffold-
generated code. If things are still being funky, I’d add a debugger
statement before line 10 and then inspect the @jobs object. It should
be an array of Job objects.

-Danimal

On Apr 24, 6:22 am, Simon H. [email protected]