I’m having an issue making an app that plays music in rails. I can’t

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Asked: May 27, 20262026-05-27T22:54:07+00:00 2026-05-27T22:54:07+00:00

I’m having an issue making an app that plays music in rails. I can’t

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I’m having an issue making an app that plays music in rails. I can’t seem to actually obtain the properties of the songs from the database. The model class is named ‘Music’. The error I get is this:

uninitialized constant Music::Title

When trying to run this code:

<div id="player">

<% @musics.each do |song| %>


<%= song.title %>
<div>Play sound #1: <a href="#" onclick="play('sound1');">play</a></div>



<% end %>
<%= initialize_sounds(sounds, debug=false) %>

The properties of the Music Class are

create_table "musics", :force => true do |t|

    t.integer  "song_id"
    t.string   "title"
    t.string   "tracklist"
    t.string   "info"
    t.string   "music_location"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

What’s interesting is that if I take out the song.title, I will get two entries of the ‘play sound #1 div’. Which means that it recognizes that there are two entries in the database. What am I doing wrong to obtain the properties from the model? This is being viewed through a rendered partial. I was able to do something similar with a posts model in the app and it worked fine. I created a database query called @musics to find the songs. I tried changing the variable from @musics to @songs in case the app got confused but no luck. Also, if I use the standard scaffold to view the index of the songs, they all show up fine. Any suggestions would be greatly appreciated.

—Update——
Here is the music.rb file:

class Music < ActiveRecord::Base
  has_one :title
  has_one :music_location
  validates_uniqueness_of :song_id


  def self.save(upload)
    name = upload['datafile']
    directory = "public/music/"
    # create the file path
    path = File.join(directory, name)
    #write the file
    File.open(path, "wb") { |f| f.write(upload['datafile'])}

  end

  def self.player
    find(:all, :conditions=> "select == true")
  end


end

And here is the development log info:

Started GET "/" for 127.0.0.1 at 2011-12-31 08:28:53 -0600
  Processing by PagesController#_home as HTML
  [1m[35mMusic Load (0.0ms)[0m  SELECT "musics".* FROM "musics" 
  [1m[36mPost Load (0.0ms)[0m  [1mSELECT "posts".* FROM "posts" [0m
Rendered posts/_news.html.erb (24.0ms)
Rendered pages/_home.html.erb within layouts/application (28.0ms)
  [1m[35mCACHE (0.0ms)[0m  SELECT "posts".* FROM "posts" 
Rendered posts/_news.html.erb (1.0ms)
Rendered pages/_home.html.erb (2.0ms)
Rendered musics/_player.html.erb (5.0ms)
Rendered pages/_music.html.erb (11.0ms)
Completed 500 Internal Server Error in 93ms

ActionView::Template::Error (uninitialized constant Music::Title):
    3:  <% @musics.each do |song| %>

    4:  

    5:  

    6:  <%= song.title %>

    7:  <div>Play sound #1: <a href="#" onclick="play('sound1');">play</a></div>

    8:  

    9:  

  app/views/musics/_player.html.erb:6:in `block in _app_views_musics__player_html_erb__288302969_49298280'
  app/views/musics/_player.html.erb:3:in `each'
  app/views/musics/_player.html.erb:3:in `_app_views_musics__player_html_erb__288302969_49298280'
  app/views/pages/_music.html.erb:12:in `_app_views_pages__music_html_erb___111175075_22835100'
  app/views/layouts/application.html.erb:48:in `_app_views_layouts_application_html_erb__149306977_49748748'

Rendered c:/Ruby192/lib/ruby/gems/1.9.1/gems/actionpack-3.1.1/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.0ms)
Rendered c:/Ruby192/lib/ruby/gems/1.9.1/gems/actionpack-3.1.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (1.0ms)
Rendered c:/Ruby192/lib/ruby/gems/1.9.1/gems/actionpack-3.1.1/lib/action_dispatch/middleware/templates/rescues/template_error.erb within rescues/layout (24.0ms)

and the full trace

activerecord (3.1.1) lib/active_record/base.rb:1341:in `compute_type'
activerecord (3.1.1) lib/active_record/reflection.rb:173:in `klass'
activerecord (3.1.1) lib/active_record/associations/association.rb:118:in `klass'
activerecord (3.1.1) lib/active_record/associations/association.rb:166:in `find_target?'
activerecord (3.1.1) lib/active_record/associations/association.rb:138:in `load_target'
activerecord (3.1.1) lib/active_record/associations/association.rb:56:in `reload'
activerecord (3.1.1) lib/active_record/associations/singular_association.rb:9:in `reader'
activerecord (3.1.1) lib/active_record/associations/builder/association.rb:41:in `block in define_readers'
app/views/musics/_player.html.erb:6:in `block in _app_views_musics__player_html_erb__288302969_39714996'
app/views/musics/_player.html.erb:3:in `each'
app/views/musics/_player.html.erb:3:in `_app_views_musics__player_html_erb__288302969_39714996'
actionpack (3.1.1) lib/action_view/template.rb:144:in `block in render'
activesupport (3.1.1) lib/active_support/notifications.rb:55:in `instrument'
actionpack (3.1.1) lib/action_view/template.rb:142:in `render'
actionpack (3.1.1) lib/action_view/renderer/partial_renderer.rb:256:in `render_partial'
actionpack (3.1.1) lib/action_view/renderer/partial_renderer.rb:228:in `block (2 levels) in render'
actionpack (3.1.1) lib/action_view/renderer/abstract_renderer.rb:33:in `block in instrument'
activesupport (3.1.1) lib/active_support/notifications.rb:53:in `block in instrument'
activesupport (3.1.1) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.1) lib/active_support/notifications.rb:53:in `instrument'
actionpack (3.1.1) lib/action_view/renderer/abstract_renderer.rb:33:in `instrument'
actionpack (3.1.1) lib/action_view/renderer/partial_renderer.rb:227:in `block in render'
actionpack (3.1.1) lib/action_view/renderer/abstract_renderer.rb:22:in `wrap_formats'
actionpack (3.1.1) lib/action_view/renderer/partial_renderer.rb:219:in `render'
actionpack (3.1.1) lib/action_view/renderer/renderer.rb:41:in `render_partial'
actionpack (3.1.1) lib/action_view/helpers/rendering_helper.rb:27:in `render'
app/views/pages/_music.html.erb:12:in `_app_views_pages__music_html_erb___111175075_22835100'
actionpack (3.1.1) lib/action_view/template.rb:144:in `block in render'
activesupport (3.1.1) lib/active_support/notifications.rb:55:in `instrument'
actionpack (3.1.1) lib/action_view/template.rb:142:in `render'
actionpack (3.1.1) lib/action_view/renderer/partial_renderer.rb:256:in `render_partial'
actionpack (3.1.1) lib/action_view/renderer/partial_renderer.rb:228:in `block (2 levels) in render'
actionpack (3.1.1) lib/action_view/renderer/abstract_renderer.rb:33:in `block in instrument'
activesupport (3.1.1) lib/active_support/notifications.rb:53:in `block in instrument'
activesupport (3.1.1) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.1) lib/active_support/notifications.rb:53:in `instrument'
actionpack (3.1.1) lib/action_view/renderer/abstract_renderer.rb:33:in `instrument'
actionpack (3.1.1) lib/action_view/renderer/partial_renderer.rb:227:in `block in render'
actionpack (3.1.1) lib/action_view/renderer/abstract_renderer.rb:22:in `wrap_formats'
actionpack (3.1.1) lib/action_view/renderer/partial_renderer.rb:219:in `render'
actionpack (3.1.1) lib/action_view/renderer/renderer.rb:41:in `render_partial'
actionpack (3.1.1) lib/action_view/helpers/rendering_helper.rb:27:in `render'
app/views/layouts/application.html.erb:48:in `_app_views_layouts_application_html_erb__149306977_49748748'
actionpack (3.1.1) lib/action_view/template.rb:144:in `block in render'
activesupport (3.1.1) lib/active_support/notifications.rb:55:in `instrument'
actionpack (3.1.1) lib/action_view/template.rb:142:in `render'
actionpack (3.1.1) lib/action_view/renderer/template_renderer.rb:52:in `render_with_layout'
actionpack (3.1.1) lib/action_view/renderer/template_renderer.rb:38:in `render_template'
actionpack (3.1.1) lib/action_view/renderer/template_renderer.rb:12:in `block in render'
actionpack (3.1.1) lib/action_view/renderer/abstract_renderer.rb:22:in `wrap_formats'
actionpack (3.1.1) lib/action_view/renderer/template_renderer.rb:9:in `render'
actionpack (3.1.1) lib/action_view/renderer/renderer.rb:36:in `render_template'
actionpack (3.1.1) lib/action_view/renderer/renderer.rb:17:in `render'
actionpack (3.1.1) lib/abstract_controller/rendering.rb:120:in `_render_template'
actionpack (3.1.1) lib/action_controller/metal/streaming.rb:250:in `_render_template'
actionpack (3.1.1) lib/abstract_controller/rendering.rb:114:in `render_to_body'
actionpack (3.1.1) lib/action_controller/metal/renderers.rb:30:in `render_to_body'
actionpack (3.1.1) lib/action_controller/metal/compatibility.rb:43:in `render_to_body'
actionpack (3.1.1) lib/abstract_controller/rendering.rb:99:in `render'
actionpack (3.1.1) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (3.1.1) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
activesupport (3.1.1) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
c:/Ruby192/lib/ruby/1.9.1/benchmark.rb:310:in `realtime'
activesupport (3.1.1) lib/active_support/core_ext/benchmark.rb:5:in `ms'
actionpack (3.1.1) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
actionpack (3.1.1) lib/action_controller/metal/instrumentation.rb:78:in `cleanup_view_runtime'
activerecord (3.1.1) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime'
actionpack (3.1.1) lib/action_controller/metal/instrumentation.rb:39:in `render'
actionpack (3.1.1) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (3.1.1) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.1.1) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.1.1) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.1.1) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.1.1) lib/active_support/callbacks.rb:425:in `_run__593797494__process_action__1048922870__callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:386:in `_run_process_action_callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.1) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.1.1) lib/action_controller/metal/rescue.rb:17:in `process_action'
actionpack (3.1.1) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.1.1) lib/active_support/notifications.rb:53:in `block in instrument'
activesupport (3.1.1) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.1) lib/active_support/notifications.rb:53:in `instrument'
actionpack (3.1.1) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.1.1) lib/action_controller/metal/params_wrapper.rb:201:in `process_action'
activerecord (3.1.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.1.1) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.1.1) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.1.1) lib/action_controller/metal.rb:193:in `dispatch'
actionpack (3.1.1) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.1.1) lib/action_controller/metal.rb:236:in `block in action'
actionpack (3.1.1) lib/action_dispatch/routing/route_set.rb:65:in `call'
actionpack (3.1.1) lib/action_dispatch/routing/route_set.rb:65:in `dispatch'
actionpack (3.1.1) lib/action_dispatch/routing/route_set.rb:29:in `call'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:152:in `block in call'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:96:in `block in recognize'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:75:in `optimized_each'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:95:in `recognize'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:141:in `call'
actionpack (3.1.1) lib/action_dispatch/routing/route_set.rb:532:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.3.5) lib/rack/etag.rb:23:in `call'
rack (1.3.5) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/flash.rb:243:in `call'
rack (1.3.5) lib/rack/session/abstract/id.rb:195:in `context'
rack (1.3.5) lib/rack/session/abstract/id.rb:190:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/cookies.rb:331:in `call'
activerecord (3.1.1) lib/active_record/query_cache.rb:62:in `call'
activerecord (3.1.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:477:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (3.1.1) lib/active_support/callbacks.rb:392:in `_run_call_callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.1) lib/action_dispatch/middleware/callbacks.rb:28:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/reloader.rb:68:in `call'
rack (1.3.5) lib/rack/sendfile.rb:101:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.1.1) lib/rails/rack/logger.rb:13:in `call'
rack (1.3.5) lib/rack/methodoverride.rb:24:in `call'
rack (1.3.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.1.1) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.3.5) lib/rack/lock.rb:15:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/static.rb:53:in `call'
railties (3.1.1) lib/rails/engine.rb:456:in `call'
railties (3.1.1) lib/rails/rack/content_length.rb:16:in `call'
railties (3.1.1) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.3.5) lib/rack/handler/webrick.rb:59:in `service'
c:/Ruby192/lib/ruby/1.9.1/webrick/httpserver.rb:111:in `service'
c:/Ruby192/lib/ruby/1.9.1/webrick/httpserver.rb:70:in `run'
c:/Ruby192/lib/ruby/1.9.1/webrick/server.rb:183:in `block in start_thread'

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1 Answer

Editorial Team · Answer 1 · 2026-05-27T22:54:07+00:00

Editorial Team

2026-05-27T22:54:07+00:00Added an answer on May 27, 2026 at 10:54 pm

Remove has_one :title and has_one :music_location from your Music model.

And you probably should have a belongs_to :song as well.

I don’t think you understand what has_one does. When you say: has_one :title, it would mean that there is a Titles table, with a music_id column.

You don’t need to do anything in your model to be able to write song.title, it’s just an attribute of the Music model.

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