Link_to: link is missing id

I’m using a legacy table, where the unique id is not ‘id’
I have a Model class like the following:

class Article < ActiveRecord::Base
set_primary_key “ARTICLE_ID”

however, using a link_to like the following (modified scaffolding),
the link has no id value:

<% for article in @articles %>

<% for column in Article.content_columns %> <%=h article.send( %> <% end %> <%= link_to 'Show', :action => 'show_article', :id => article %> <%= link_to 'Edit', :action => 'edit_article', :id => article %> <%= link_to 'Destroy', { :action => 'destroy_article', :id => article }, :confirm => 'Are you sure?', :post => true %> <% end %> (In case this gets rendered as HTML, the link in question is: <%= link_to 'Show', :action => 'show_article', :id => article %>)

The link looks like “/controller/show_article/”
Instead of “/controller/show_article/43”

What’s up?

Rails console:

article = Article.find(:first)
=> #<Article:0x5bd7858 @attributes={“article_headline”=>"…",
“byline”=>nil, “display_date”=>Tue Oct 17 00:01:00 GMT-5:00 2000,
“status”=>“PUB”, “print_page”=>nil, “hot_code”=>“N”,
“headline”=>"…", “creation_date”=>Mon Jul 09 15:39:04 GMT-5:00 2001,
“article_type”=>"…", “flashline”=>nil, “publication”=>"…",
“base_doc_id”=>"…", “summary”=>"…", “file_location”=>“C”,
“page”=>"…", “display_name”=>"…",
“rev_doc_id”=>"…", “article_id”=>329901.0, “section”=>"…",
“source”=>"…", “to_be_purged”=>1.0}>
=> nil

Try calling article.to_param and see what it returns. I would guess
that is where your problem is since you are defining your own primary
key. Perhaps this is a bug in rails?

If that is the case, you can fix it by either implementing your
to_param to return your article_id, or passing :id =>


On 7/7/06, Dean H. [email protected] wrote:

<% for article in @articles %>
(In case this gets rendered as HTML, the link in question is: <%=
“byline”=>nil, “display_date”=>Tue Oct 17 00:01:00 GMT-5:00 2000,

Rails mailing list
[email protected]

Tom D.

thanks, I didn’t know about to_param (I was digging through rails
source trying to figure out how link_to turned the object into an id
to track this down)

=> nil

yeah, I think it might be a bug, but I’d like someone to confirm that
I’m doing things right. for now I guess I’ll implement the to_param,
but I would like not to have to do this.

Also, I expected that using “set_primary_key” would provide an “id”
attribute to the model, but it’s nil.

well, I think I just solved it.

#set_primary_key “ARTICLE_ID”
set_primary_key “article_id”

and it worked.

Here’s why:
def id
attr_name = self.class.primary_key
column = column_for_attribute(attr_name)
define_read_method(:id, attr_name, column) if

I just read about the to_param today in this mailing list :slight_smile:

That makes sense. So the primary key is either case sensitive or just
needs to be all lower case. I haven’t had to use the set_primary_key


On 7/7/06, Dean H. [email protected] wrote:

    attr_name = self.class.primary_key

to track this down)

the link has no id value:

>> article = Article.find(:first) => nil

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[email protected]

Tom D.

sorry, my hand slipped :slight_smile:


column = article.column_for_attribute(“ARTICLE_ID”)
=> nil

column = article.column_for_attribute(“article_id”)
=> #<ActiveRecord::ConnectionAdapters::OracleColumn:0x53b4640
@limit=nil, @scale
=nil, @text=false, @sql_type=“NUMBER”, @name=“article_id”,
@primary=false, @null
=false, @default=nil, @type=:float, @number=true>