Jourdein

Last night, found a problem in codes during updating form for a has_many relationship model. Rather than updating the record, it created a new one.

The solution is in railscasts episode 75.

Consider contact that has_many contact_email addresses. Created

def contact_email_attributes=(contact_email_attributes)
  contact_email_attributes  do |attributes|
    contact_emails.build(attributes)
  end
end

Changed to this one:

def contact_email_attributes=(contact_email_attributes)
  contact_email_attributes.each  do |attributes|
    if attributes[:id].blank?
      contact_emails.build(attributes)
    else
      contact_email = contact_emails.detect { |e| e.id == attributes[:id].to_i }
      contact_email.attributes = attributes
    end
  end
end

that will updates contact_email if there’s :id attributes. Then, I need to add the :id inside the form as hidden_field_tag:

- @contact.contact_emails.each do |contact_email|
...
= hidden_field_tag "contact[contact_email_attributes][][id]", contact_email.id
...

And that’s all. It’s done.

In the form, you could do fields_for rather than using _tag methods. In fact, my original code was using that but after I tried everything and it ended up with the _tag methods, I was lazy to change it back. By the way, it works both ways…