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PObasic rails model has_many and belongs_to with group by date
 

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  1. PObasic rails model has_many and belongs_to with group by date
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    <p>I'm a rails newbie so pardon if this is a basic question. I'm setting up some models and the relationships should be pretty basic, but I'm a little stuck in the best way to set everything up.</p> <p>I'm trying to display a list of seminars that have different times. Here are my two tables:</p> <pre><code>create_table "seminars", :force =&gt; true do |t| t.string "name" t.datetime "created_at", :null =&gt; false t.datetime "updated_at", :null =&gt; false end create_table "seminar_times", :force =&gt; true do |t| t.datetime "start_date" t.datetime "end_date" t.integer "seminar_id" t.datetime "created_at", :null =&gt; false t.datetime "updated_at", :null =&gt; false end </code></pre> <p>I'd like to display my seminars at localhost:3000/seminars like so:</p> <pre><code>Intro To Rails Aug 1 3-5pm and 6-8pm How To Juggle Aug 10 6-8pm Stackoverflow Rocks Aug 13 2-5pm or 6-8pm </code></pre> <p>One seminar can have many different seminar times (which is why i put them into two separate tables). To do this normally with straight SQL I'd join the tables, order by start_date, then group by DAY and by seminar id.</p> <p>How would I do this the "rails way"?</p> <p>Here's what I've done so far, but it doesn't seem like the right way to go.</p> <p>Seminar model:</p> <pre><code>class Seminar &lt; ActiveRecord::Base attr_accessible :name has_many :seminar_times, :dependent =&gt; :destroy validates :name, :presence =&gt; true end </code></pre> <p>SeminarTime model:</p> <pre><code>class SeminarTime &lt; ActiveRecord::Base attr_accessible :end_date, :seminar_id, :start_date belongs_to :seminar, :foreign_key =&gt; 'seminar_id' default_scope :order =&gt; 'start_date' end </code></pre> <p>seminars_controller:</p> <pre><code>def index @seminars = SeminarTime.group('date(start_date), seminar_id') #THIS LINE ESPECIALLY SEEMS WRONG TO ME respond_to do |format| format.html # index.html.erb format.json { render json: @seminars } end end </code></pre> <p>seminar_times_controller:</p> <pre><code>def index @seminar_times = SeminarTime.all respond_to do |format| format.html # index.html.erb format.json { render json: @seminar_times } end end </code></pre> <p>routes.rb</p> <pre><code>resources :seminars resources :seminar_times root to: 'static_pages#home' match '/seminars', to: 'seminars#index' </code></pre> <p>views/seminars/index.html.erb:</p> <pre><code>#this also needs some work. i'm not sure how to loop into that group by statement &lt;% @seminars.each do |seminar| %&gt; &lt;%= seminar.seminar.name %&gt; &lt;%= seminar.start_date %&gt; &lt;%= seminar.end_date %&gt; &lt;% end %&gt; </code></pre> <p>I've tried also getting everything through the seminar_times_controller and then routing /seminars to: match '/seminars', to: 'seminar_times#index' but that also seems kinda off to me.</p> <p>Hopefully I'm being clear enough. Any guidance is much appreciated. Thanks!</p> <hr> <p>My app evolved some since I asked this question. I ended up adding some categories, so I made a shared module so I could use my sorting code throughout the app. The sort and grouping looks like this:</p> <pre><code>module Shared def self.category_group_by_day(categories_array) seminars = Seminar.joins(:seminar_times, :categories). where(:categories =&gt; {:name =&gt; categories_array}). where("date(start_time) &gt; ?", DateTime.now) seminars.sort_by! { |s| s.start_date } seminar_days = seminars.group_by { |s| [s.start_date.beginning_of_day, s.course_id] } end end </code></pre> <p>I call it in my controller like this:</p> <pre><code>@seminar_days = Shared::category_group_by_day(['Free Seminar', 'Online Seminar']) </code></pre> <p>And then in my view:</p> <pre><code>&lt;% @seminar_days.keys.sort.each do |day| %&gt; &lt;%= @seminar_days[day].first.course_name %&gt; &lt;%= day.to_s.to_date.strftime("%b %e") %&gt; &lt;%= day.to_s.to_date.strftime("%a") %&gt; &lt;% for seminar in @seminar_days[day] %&gt; &lt;div&gt; &lt;%= seminar.start_date.strftime("%l").strip %&gt;—&lt;%= seminar.end_date.strftime("%l").strip %&gt; &lt;%= seminar.end_date.strftime("%p") %&gt; &lt;/div&gt; &lt;% end %&gt; &lt;% end %&gt; </code></pre>
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    1. COyou can omit the :foreign_key => 'seminar_id' - that's the convention.
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