Using has many :through

Question

Using has_many => through association.

Here is what i have.

:planning model

has_many :acttypes
has_many :actcategories
has_many :acts, :through => :actcategories

:acts model

belongs_to :acttype
has_many :actcategories
has_many :plannings, :through => :actcategories

:actcategories model

named_scope :theacts, lambda { |my_id|
{:conditions => ['planning_id = ?', my_id] }} 
belongs_to :act
belongs_to :planning

:acttype model

has_many :acts

My Problem Starts here. I need to show all Acts by each Act Type from Plannings that is part of the actcategories association Right now i am getting all the acts and missing the actcategories association.

Planning Controller

def show
@planning = Planning.find(params[:id])
@acttypes = Acttype.find(:all, :include => :acts)
@acts = Actcategory.theacts(@planning)
end

Planning Show View

<% @acttypes.each do |acttype|%>
<%= acttype.name %>

<% @acts.each do |acts| %>
<li><%= link_to acts.act.name, myacts_path(acts.act, :planning => @planning.id) %></li>
<% end %>
<% end -%>

Thanks for any help.

Answer 1

I think the key thing you're missing is that finders and named scopes only return the Class that they're called on.

@acts = Actcategory.theacts(@planning)

@acts is all the Actcategories where actcategories.planning_id = @planning.id. They don't necessarily have the required act type.

Really, what I think you're looking for is this named scope:

class Act < ActiveRecord::Base
  named_scope :with_planning, lambda do |planning_id|
   { :joins => :actcategories, 
    :conditions => {:actcategories => {:planning_id => planning_id}}
   }
  ...
end

Which limits acts to those associated with the given planning. This can be called on an association to limit the linked acts to those associated with a specific planning.

Example: @acts contains acts of acttype, x, that are associated with planning, y.

@acts = Acttype.find(x).acts.with_planning(y)

With this named scope this code should accomplish what you were aiming for.

controller:

def show
  @planning = Planning.find(params[:id])
  @acttypes = Acttype.find(:all, :include => :acts)
end

view:

<% @acttypes.each do |acttype| %>
<h2> <%= acttype.name %><h2>
  <% acttype.acts.with_planning(@planning) do |act| %>
    This act belongs to acttype <%= acttype.name%> and 
     is associated to <%=@planning.name%> through 
     actcatgetories: <%=act.name%>
  <%end%>
<%end%>