在轨道4中使用包含和深层嵌套

Question

I have 3 Models.

  ProjectDate (available dates for a project) which 
  has_many Events

  Events (the appointments on any given ProjectDate)
  belongs_to ProjectDate
  belongs_to User

  User (the person who created the Event)
  has_many Events

I am wondering how I can use includes (or if I can use includes) to fetch the User attributes associated with an Event when I'm also fetching all the Events associated with a ProjectDate.

I want to be able to pull the user.firstname (see view code below)

This is how I fetch an array of ProjectDats with their associated Events:

     @projectschedule  = ProjectDate.where(project_id: params[:p]).includes(:events).order(the_date: :asc)

I am really stuck.

Here is the view code:

    <table width="100%;" class="">
      <tr>
        <td >
          <%=p.the_date.strftime("%A")%><br>
            <%=p.the_date.strftime("%b. %d ")%>
          </td>
          <td class="dateinfo"><%   p.events.users.each do |e| %>
             <ul >
               <li ><%= e.starts_on.strftime("%l:%m %P ") %><%= e.user.firstname %><%= e.description %><button >O</button><button >O</button></li>
            </ul><% end %> 
           </td>
         </tr>
       </table>
 <% end %> 

Answer 1

You can nest include arguments like this.

@projectschedule  = ProjectDate.where(project_id: params[:p]).includes(events: :user).order(the_date: :asc)

Note events: :user , which will make sure both events and it's user are eager loaded.