¿Por qué obtengo un método indefinido `join 'for nil: error de NilClass?

tengo este código en mi archivo "index.html.erb" en mi proyecto:¿Por qué obtengo un método indefinido `join 'for nil: error de NilClass?

<h1>Listing businesses</h1> 

<table> 
<tr> 
    <th>Index</th> 
    <th>Name</th> 
    <th>Phone Number</th> 
    <th>Suite</th> 
    <th>Address</th> 
    <th>City</th> 
<th>Province</th> 
<th>Postal Code</th> 
<th>Fax</th> 
    <th>Latitude</th> 
    <th>Longitude</th> 
    <th>Website</th> 
    </tr> 

<% count = 0 %> 
<% @businesses.each do |business| %> 
<!--<%=business.inspect %> <br> <br>--> 
<%count = count.to_i + 1 %> 
<tr> 
    <td><%= count %></td> 
    <td><%= business.name %></td> 
    <td><%= business.phone %></td> 
    <td><%= business.suite %></td> 
    <td><%= business.address %></td> 
    <td><%= business.city %></td> 
    <td><%= business.province %></td> 
    <td><%= business.phone %></td> 
    <td><%= business.postalcode %></td> 
    <td><%= business.fax %></td> 
    <td><%= business.latitude %></td> 
    <td><%= business.longitude %></td> 
    <td><%= business.website %></td> 
    <td><%= link_to 'Show', business %></td> 
    <td><%= link_to 'Edit', edit_business_path(business) %></td> 
    <td><%= link_to 'Destroy', user, confirm: 'Are you sure?', method: :delete %></td> 
</tr> 
<% end %> 
</table>

Cuando voy a la siguiente dirección:

http://localhost:3000/businesses/

estoy recibiendo este error:

NoMethodError in Businesses#index 

Showing /Users/AM/Documents/RailsWS/cmdLineWS/Directory/app/views/businesses/index.html.erb where line #37 raised: 

undefined method `join' for nil:NilClass 
Extracted source (around line #37): 

34:  <td><%= business.latitude %></td> 
35:  <td><%= business.longitude %></td> 
36:  <td><%= business.website %></td> 
37:  <td><%= link_to 'Show', business %></td> 
38:  <td><%= link_to 'Edit', edit_business_path(business) %></td> 
39:  <td><%= link_to 'Destroy', user, confirm: 'Are you sure?', method: :delete %></td> 
40: </tr> 
Rails.root: /Users/AM/Documents/RailsWS/cmdLineWS/Directory

¿Alguna idea de qué está pasando?

Aquí está la pila de llamadas completa:

activemodel (3.2.1) lib/active_model/conversion.rb:52:in `to_param' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:417:in `block in <class:Generator>' 
journey (1.0.3) lib/journey/formatter.rb:31:in `call' 
journey (1.0.3) lib/journey/formatter.rb:31:in `block (2 levels) in generate' 
journey (1.0.3) lib/journey/formatter.rb:30:in `each' 
journey (1.0.3) lib/journey/formatter.rb:30:in `block in generate' 
journey (1.0.3) lib/journey/formatter.rb:58:in `match_route' 
journey (1.0.3) lib/journey/formatter.rb:16:in `generate' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:510:in `generate' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:551:in `generate' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:576:in `url_for' 
actionpack (3.2.1) lib/action_dispatch/routing/url_for.rb:148:in `url_for' 
actionpack (3.2.1) lib/action_view/helpers/url_helper.rb:107:in `url_for' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:202:in `business_path' 
app/views/businesses/index.html.erb:37:in `block in _app_views_businesses_index_html_erb___1138300221443858101_2152537040' 
app/views/businesses/index.html.erb:20:in `each' 
app/views/businesses/index.html.erb:20:in `_app_views_businesses_index_html_erb___1138300221443858101_2152537040' 
actionpack (3.2.1) lib/action_view/template.rb:143:in `block in render' 
activesupport (3.2.1) lib/active_support/notifications.rb:125:in `instrument' 
actionpack (3.2.1) lib/action_view/template.rb:141:in `render' 
actionpack (3.2.1) lib/action_view/renderer/template_renderer.rb:41:in `block (2 levels) in render_template' 
actionpack (3.2.1) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument' 
activesupport (3.2.1) lib/active_support/notifications.rb:123:in `block in instrument' 
activesupport (3.2.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument' 
activesupport (3.2.1) lib/active_support/notifications.rb:123:in `instrument' 
actionpack (3.2.1) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument' 
actionpack (3.2.1) lib/action_view/renderer/template_renderer.rb:40:in `block in render_template' 
actionpack (3.2.1) lib/action_view/renderer/template_renderer.rb:48:in `render_with_layout' 
actionpack (3.2.1) lib/action_view/renderer/template_renderer.rb:39:in `render_template' 
actionpack (3.2.1) lib/action_view/renderer/template_renderer.rb:12:in `render' 
actionpack (3.2.1) lib/action_view/renderer/renderer.rb:36:in `render_template' 
actionpack (3.2.1) lib/action_view/renderer/renderer.rb:17:in `render' 
actionpack (3.2.1) lib/abstract_controller/rendering.rb:109:in `_render_template' 
actionpack (3.2.1) lib/action_controller/metal/streaming.rb:225:in `_render_template' 
actionpack (3.2.1) lib/abstract_controller/rendering.rb:103:in `render_to_body' 
actionpack (3.2.1) lib/action_controller/metal/renderers.rb:28:in `render_to_body' 
actionpack (3.2.1) lib/action_controller/metal/compatibility.rb:50:in `render_to_body' 
actionpack (3.2.1) lib/abstract_controller/rendering.rb:88:in `render' 
actionpack (3.2.1) lib/action_controller/metal/rendering.rb:16:in `render' 
actionpack (3.2.1) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render' 
activesupport (3.2.1) lib/active_support/core_ext/benchmark.rb:5:in `block in ms' 
/Users/AM/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/benchmark.rb:310:in `realtime' 
activesupport (3.2.1) lib/active_support/core_ext/benchmark.rb:5:in `ms' 
actionpack (3.2.1) lib/action_controller/metal/instrumentation.rb:40:in `block in render' 
actionpack (3.2.1) lib/action_controller/metal/instrumentation.rb:83:in `cleanup_view_runtime' 
activerecord (3.2.1) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime' 
actionpack (3.2.1) lib/action_controller/metal/instrumentation.rb:39:in `render' 
actionpack (3.2.1) lib/action_controller/metal/implicit_render.rb:10:in `default_render' 
actionpack (3.2.1) lib/action_controller/metal/mime_responds.rb:268:in `block in retrieve_response_from_mimes' 
actionpack (3.2.1) lib/action_controller/metal/mime_responds.rb:195:in `call' 
actionpack (3.2.1) lib/action_controller/metal/mime_responds.rb:195:in `respond_to' 
app/controllers/businesses_controller.rb:5:in `index' 
actionpack (3.2.1) lib/action_controller/metal/implicit_render.rb:4:in `send_action' 
actionpack (3.2.1) lib/abstract_controller/base.rb:167:in `process_action' 
actionpack (3.2.1) lib/action_controller/metal/rendering.rb:10:in `process_action' 
actionpack (3.2.1) lib/abstract_controller/callbacks.rb:18:in `block in process_action' 
activesupport (3.2.1) lib/active_support/callbacks.rb:414:in `_run__4378774651029744650__process_action__1974792849221574797__callbacks' 
activesupport (3.2.1) lib/active_support/callbacks.rb:405:in `__run_callback' 
activesupport (3.2.1) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks' 
activesupport (3.2.1) lib/active_support/callbacks.rb:81:in `run_callbacks' 
actionpack (3.2.1) lib/abstract_controller/callbacks.rb:17:in `process_action' 
actionpack (3.2.1) lib/action_controller/metal/rescue.rb:29:in `process_action' 
actionpack (3.2.1) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action' 
activesupport (3.2.1) lib/active_support/notifications.rb:123:in `block in instrument' 
activesupport (3.2.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument' 
activesupport (3.2.1) lib/active_support/notifications.rb:123:in `instrument' 
actionpack (3.2.1) lib/action_controller/metal/instrumentation.rb:29:in `process_action' 
actionpack (3.2.1) lib/action_controller/metal/params_wrapper.rb:205:in `process_action' 
activerecord (3.2.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action' 
actionpack (3.2.1) lib/abstract_controller/base.rb:121:in `process' 
actionpack (3.2.1) lib/abstract_controller/rendering.rb:45:in `process' 
actionpack (3.2.1) lib/action_controller/metal.rb:203:in `dispatch' 
actionpack (3.2.1) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch' 
actionpack (3.2.1) lib/action_controller/metal.rb:246:in `block in action' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:66:in `call' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:66:in `dispatch' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:30:in `call' 
journey (1.0.3) lib/journey/router.rb:68:in `block in call' 
journey (1.0.3) lib/journey/router.rb:56:in `each' 
journey (1.0.3) lib/journey/router.rb:56:in `call' 
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:589:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call' 
rack (1.4.1) lib/rack/etag.rb:23:in `call' 
rack (1.4.1) lib/rack/conditionalget.rb:25:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/head.rb:14:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/params_parser.rb:21:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/flash.rb:242:in `call' 
rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context' 
rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/cookies.rb:338:in `call' 
activerecord (3.2.1) lib/active_record/query_cache.rb:64:in `call' 
activerecord (3.2.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:443:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call' 
activesupport (3.2.1) lib/active_support/callbacks.rb:405:in `_run__539745845193235082__call__2953064504705011211__callbacks' 
activesupport (3.2.1) lib/active_support/callbacks.rb:405:in `__run_callback' 
activesupport (3.2.1) lib/active_support/callbacks.rb:385:in `_run_call_callbacks' 
activesupport (3.2.1) lib/active_support/callbacks.rb:81:in `run_callbacks' 
actionpack (3.2.1) lib/action_dispatch/middleware/callbacks.rb:27:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/reloader.rb:65:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/remote_ip.rb:31:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call' 
railties (3.2.1) lib/rails/rack/logger.rb:26:in `call_app' 
railties (3.2.1) lib/rails/rack/logger.rb:16:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/request_id.rb:22:in `call' 
rack (1.4.1) lib/rack/methodoverride.rb:21:in `call' 
rack (1.4.1) lib/rack/runtime.rb:17:in `call' 
activesupport (3.2.1) lib/active_support/cache/strategy/local_cache.rb:72:in `call' 
rack (1.4.1) lib/rack/lock.rb:15:in `call' 
actionpack (3.2.1) lib/action_dispatch/middleware/static.rb:53:in `call' 
railties (3.2.1) lib/rails/engine.rb:479:in `call' 
railties (3.2.1) lib/rails/application.rb:220:in `call' 
rack (1.4.1) lib/rack/content_length.rb:14:in `call' 
railties (3.2.1) lib/rails/rack/log_tailer.rb:14:in `call' 
rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service' 
/Users/AM/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/httpserver.rb:111:in `service' 
/Users/AM/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/httpserver.rb:70:in `run' 
/Users/AM/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/server.rb:183:in `block in start_thread'

Modelo para la aplicación es archivo llamado business.rb que contiene lo siguiente:

class Business < ActiveRecord::Base 
    establish_connection "Listings_development" 
end

Fuente

2012-03-09 banditKing

Do usted anula 'to_key' en su modelo? ¿Qué devuelve 'business.to_key'? –

Sería genial si pudiera publicar el código del modelo para 'Business' :) – summea

@summea el código del modelo de la empresa se ha agregado a la publicación – banditKing

Dado que no parece su mesa para tener una clave primaria , lea el Rails Migrations Guide y escriba uno para agregar la columna id a su tabla.

def change 
    add_column :business, :id, :primary_key 
end

Como se describe in the documentation of the to_param method, devuelve nil si el objeto todavía no se ha persistido.

Esto se debe a que un enlace a un objeto que no está en la base de datos es en realidad un enlace roto. Asegúrese de que su objeto se esté guardando antes de intentar vincularlo.

<td><%= link_to 'Show', business %></td>

Eso es probable que sea el problema. ~~You must link to an URL, no a un modelo~~. Use un ayudante para obtener una que se refiere al objeto:

<td><%= link_to 'Show', business_path(business) %></td>

El mismo problema se producirá aquí, supongo:

<td><%= link_to 'Destroy', user, ... %></td>

el usuario debe sustituir esa línea con:

<td><%= link_to 'Destroy', destroy_user_path(user), ... %></td>

Fuente

2012-03-09 22:34:40

No parece ser el problema – banditKing

@banditKing, ¿puedes publicar la pila de llamadas completa? –

@banditKing: no edite la respuesta de otra persona para agregar la pila de llamadas. Por favor, edite su pregunta y agréguela allí. –

¿Por qué obtengo un método indefinido `join 'for nil: error de NilClass?

Respuesta

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