Rails: many to many agony

ruby-talk
1

I have two classes: Projects and Company. There are many to many
relationships between companies and project and are joined by table
company_projects

Thing is when I render out a select list I want to make the related
dropdown items selected :

<select name="project[company_id]">
   <% @companies.each do |company| %>
       <option value="<%= company.id %>" >
         <%= ' selected' if company.id == @project.companies.id %>
         <%=company.companyName %>
       </option>
   <% end %>
</select>

However I can't seem to be able to get the project.companies.id (ie
company_project.company_id) for the related project.

I know this is pretty darn simple but I can't seem to crack it.

Any help would be appreciated!

Graham

2

I have two classes: Projects and Company
[with a many-to-many relationship]

<select name="project[company_id]">
  <% @companies.each do |company| %>
      <option value="<%= company.id %>" >
        <%= ' selected' if company.id == @project.companies.id %>

         <%= ' selected' if @project.companies.include? company %>

        <%=company.companyName %>
      </option>
  <% end %>
</select>

(Does that make a multiple-select? I thought I had to add the html_options
parameter {:multiple => 'multiple'}.)

Cheers,
Dave

···

"Graham Arrowsmith" <g.arrowsmith@gmail.com> wrote:

3

Graham Arrowsmith wrote:

I have two classes: Projects and Company. There are many to many
relationships between companies and project and are joined by table
company_projects

Thing is when I render out a select list I want to make the related
dropdown items selected :

<select name="project[company_id]">
   <% @companies.each do |company| %>
       <option value="<%= company.id %>" >
         <%= ' selected' if company.id == @project.companies.id %>
         <%=company.companyName %>
       </option>
   <% end %>
</select>

However I can't seem to be able to get the project.companies.id (ie
company_project.company_id) for the related project.

I know this is pretty darn simple but I can't seem to crack it.

Any help would be appreciated!

Graham

I've just begun using activerecord, so take my suggestion with a grain of
salt :slight_smile:

project.companies should return an array of companies, no? That makes it
wrong to say project.companies.id. I think you want something like

<%= ' selected' if @project.companies.member?(company) %>

Array#member? uses == to test for equality, and I think I remember reading
that AR overrides == to test for the equality of the "id" field so the
comparison should work.

Hope that helps.

Luca