Hi everybody,
I'm using ruby 1.9.1, with rails 2.3.*. I have an application of
products and categories, but I want each type of product to have
specific attributes. So, basically, according to the chosen category,
I want different fields to be shown for the user.
So, before actually making the association of the product with the
attribute, I want to create an administration system where the
administrators could actually select wich fields they want for each
category, in an N:N association, usign has many through
(categoryFields is the middle table). So, up to now, the structure is:
class Field < ActiveRecord::Base
has_many :categoryFields, :dependent => :destroy
has_many :categories, :through => :categoryFields
end
class CategoryField < ActiveRecord::Base
belongs_to :field
belongs_to :category
end
class Category < ActiveRecord::Base
has_many :categoryFields, :dependent => :destroy
has_many :fields, :through => :categoryFields
end
And this works perfectly.
so, now, in my Category Edit view, I want to show a list of ALL
AVAILABLE FIELDS (i.e. only those not already associated to that
specific category) at the right, and in the left, all the ASSOCIATED
FIELDS for that category. Using a simple drag-and-drop, the user can
drag fields from the right to insert them in category, or move them to
the right to remove them from that specific category.
The problem is that I don't want that any field in the left column
also appear in the right column (each field can only be used once in
that specific category, since those attributes are unique). So, once
you have associated a field to a category, it will not appear in the
list of available fields (right list). I'm coming from PHP and this is
my first rails application (I know, it's kinda complicated for a
noob).
So, what should I do, to exclude those values?
The edit method in the category controller:
@category = Category.find(params[:id])
@categories = Category.roots #the categories acts as nested set, so
we have to fetch all available parent categories
@fields = Field.all
Now, the view do the following:
<div class="category_fields span-12 last">
<% if !@category.fields.empty? # this loops through all teh
ASSOCIATED fields and display their names%>
<% @category.fields.each do |field| %>
<%=field.name%>
<% end %>
<% end %>
</div>
<div class="fields_available">
<% if !@fields.empty? # this loops through ALL THE fields and
display their names %>
<% @fields.each do |field| %>
<%=field.name%>
<% end %>
<% end %>
</div>
So, where should I place the "filter" so that only available fields
will appear in the second div? Shoud I place it in the controller, as
a condition somehow, and how? Or should I use some array-function to
"pop out" the already associated fields from the @fields array? Wich
is better from the point of view of performance, and how do I do each
of them?
Thanks a lot in advice, for any help
Samuel Brandão
web@samuelbrandao.com.br
