Rails - Apr 2006 - "for column in..." not picking up _id columns

My code executes fully:

  <% for column in ModelName.content_columns %>
    <th><%= column.human_name %></th>
  <% end %>

but it does not pick up any columns in my model''s table that end in 
"_id".

Is this by design?

Is there a helper method that will reference the related tables?  Or 
will I need to code the column titles and detail records by hand?

Learning...

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Ryan wrote:
> My code executes fully:
> 
>   <% for column in ModelName.content_columns %>
>     <th><%= column.human_name %></th>
>   <% end %>
> 
> but it does not pick up any columns in my model''s table that end
in
> "_id".
> 
> Is this by design?
> 
Yes. From http://api.rubyonrails.com/classes/ActiveRecord/Base.html#M000888

"Returns an array of column objects where the primary id, all columns 
ending in "_id" or "_count", and columns used for single
table
inheritance have been removed."
> Is there a helper method that will reference the related tables?  Or 
> will I need to code the column titles and detail records by hand?
You want to use ModelName.columns if you want the columns ending in _id.
> Learning...
http://api.rubyonrails.com/ is your friend and teacher. You can look at 
the source for content_columns if you want to reject some of the other 
columns that content_columns rejects, but keep the columns ending in _id.


-- 

Ray

Ryan wrote:
> 
> My code executes fully:
> 
>   <% for column in ModelName.content_columns %>
>     <th><%= column.human_name %></th>
>   <% end %>
> 
> but it does not pick up any columns in my model''s table that end
in
> "_id".
> 
> Is this by design?
> 
> Is there a helper method that will reference the related tables?  Or 
> will I need to code the column titles and detail records by hand?
> 
> Learning...
The ..._id columns are not "content_columns" according to rails. 
They''re used to link to other models.

If you have Company containing many People, the people table will have a 
company_id that links back to the company.

In Rails, you''d have the following models:

class Person < ActiveRecord::Base
  belongs_to :company
end

class Company < ActiveRecord::Base
  has_many :people
end

With that in place, and the correctly named _id field in the people 
table, you can do the following:

person = Person.find(:first)
person.company (this is a Company object)

or

company = Company.find(:first)
company.people (this is an array of Person objects)

You could add person to the company like this:

company.people << person

I recommend you stop typing at this point and read the Agile Web Dev 
book before going any further.  I promise it''ll be worth it.

Alan

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