ruby on rails - Why do I get a undefined method `join' for nil:NilClass error? -
i have code in "index.html.erb" file in project:
<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 |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 sure?', method: :delete %></td> </tr> <% end %> </table> when go url:
http://localhost:3000/businesses/ i'm getting error:
nomethoderror in businesses#index showing /users/am/documents/railsws/cmdlinews/directory/app/views/businesses/index.html.erb line #37 raised: undefined method `join' 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 sure?', method: :delete %></td> 40: </tr> rails.root: /users/am/documents/railsws/cmdlinews/directory any idea whats going on?
here full call stack:
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' model app file called business.rb contains this:
class business < activerecord::base establish_connection "listings_development" end
since table not seem have primary key, read rails migrations guide , write 1 add id column table.
def change add_column :business, :id, :primary_key end as described in documentation of to_param method, returns nil if object has not yet been persisted.
this because link object not in database broken link. make sure object being saved before attempting link it.
<td><%= link_to 'show', business %></td> that's problem. you must link url, not model. use helper obtain 1 refers object:
<td><%= link_to 'show', business_path(business) %></td> the same problem occur here, suppose:
<td><%= link_to 'destroy', user, ... %></td> you should replace line with:
<td><%= link_to 'destroy', destroy_user_path(user), ... %></td> 
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