如何获得可链接的标签？

Question

我正在使用这个 railscast 剧集：http://railscasts.com/episodes/382-tagging, which suggested this gem: https://github.com/mbleigh/acts-as-taggable-on，一切都很好，直到我点击了用户创建的标签 link，然后我想列出点击的标签的每个实例，但我收到了这个错误消息：

SQLite3::SQLException: near "values": syntax error: SELECT "values".* FROM "values" JOIN taggings values_taggings_5183317 ON values_taggings_5183317.taggable_id = values.id AND values_taggings_5183317.taggable_type = 'Value' AND values_taggings_5183317.tag_id = 2

你能帮帮我吗？

# _form

  <div class="form-group">
    <%= f.text_field :tag_list, class: 'form-control', placeholder: 'Enter Tag(s)' %>
  </div>
    
# Controller
    
  def index
    if params[:tag]
      @values = Value.tagged_with(params[:tag])
    else
      @values = Value.order('RANDOM()')
    end
  end

    def value_params
      params.require(:value).permit(:name, :tag_list)
    end
end
    
# index

  <td class="category">
   <b><%= raw value.tag_list.map { |t| link_to t, tag_path(t) }.join(', ') %>    </b></td>
    
# routes
    
  get 'tags/:tag', to: 'values#index', as: :tag

sqlite3 (1.3.10) lib/sqlite3/database.rb:91:in `initialize'
sqlite3 (1.3.10) lib/sqlite3/database.rb:91:in `new'
sqlite3 (1.3.10) lib/sqlite3/database.rb:91:in `prepare'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/sqlite3_adapter.rb:300:in `block in exec_query'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract_adapter.rb:466:in `block in log'
activesupport (4.2.0.rc3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract_adapter.rb:460:in `log'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/sqlite3_adapter.rb:297:in `exec_query'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract/database_statements.rb:336:in `select'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract/database_statements.rb:32:in `select_all'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract/query_cache.rb:68:in `block in select_all'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract/query_cache.rb:83:in `cache_sql'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract/query_cache.rb:68:in `select_all'
activerecord (4.2.0.rc3) lib/active_record/querying.rb:39:in `find_by_sql'
activerecord (4.2.0.rc3) lib/active_record/relation.rb:638:in `exec_queries'
activerecord (4.2.0.rc3) lib/active_record/relation.rb:514:in `load'
activerecord (4.2.0.rc3) lib/active_record/relation.rb:243:in `to_a'
activerecord (4.2.0.rc3) lib/active_record/relation/delegation.rb:46:in `each'
app/views/values/index.html.erb:10:in `_app_views_values_index_html_erb__4435347718394186207_70115274036880'
actionview (4.2.0.rc3) lib/action_view/template.rb:145:in `block in render'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:166:in `instrument'
actionview (4.2.0.rc3) lib/action_view/template.rb:333:in `instrument'
actionview (4.2.0.rc3) lib/action_view/template.rb:143:in `render'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:54:in `block (2 levels) in render_template'
actionview (4.2.0.rc3) lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `instrument'
actionview (4.2.0.rc3) lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:53:in `block in render_template'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:61:in `render_with_layout'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:52:in `render_template'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:14:in `render'
actionview (4.2.0.rc3) lib/action_view/renderer/renderer.rb:42:in `render_template'
actionview (4.2.0.rc3) lib/action_view/renderer/renderer.rb:23:in `render'
actionview (4.2.0.rc3) lib/action_view/rendering.rb:100:in `_render_template'
actionpack (4.2.0.rc3) lib/action_controller/metal/streaming.rb:217:in `_render_template'
actionview (4.2.0.rc3) lib/action_view/rendering.rb:83:in `render_to_body'
actionpack (4.2.0.rc3) lib/action_controller/metal/rendering.rb:32:in `render_to_body'
actionpack (4.2.0.rc3) lib/action_controller/metal/renderers.rb:37:in `render_to_body'
actionpack (4.2.0.rc3) lib/abstract_controller/rendering.rb:25:in `render'
actionpack (4.2.0.rc3) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:41:in `block (2 levels) in render'
activesupport (4.2.0.rc3) lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
/Users/galli01anthony/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/benchmark.rb:294:in `realtime'
activesupport (4.2.0.rc3) lib/active_support/core_ext/benchmark.rb:12:in `ms'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:41:in `block in render'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:84:in `cleanup_view_runtime'
activerecord (4.2.0.rc3) lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:40:in `render'
actionpack (4.2.0.rc3) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (4.2.0.rc3) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (4.2.0.rc3) lib/abstract_controller/base.rb:198:in `process_action'
actionpack (4.2.0.rc3) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.0.rc3) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:151:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:151:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:234:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:234:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:92:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:92:in `_run_callbacks'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:734:in `_run_process_action_callbacks'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.0.rc3) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.0.rc3) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.0.rc3) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.0.rc3) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.0.rc3) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.0.rc3) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.0.rc3) lib/action_controller/metal.rb:195:in `dispatch'
actionpack (4.2.0.rc3) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.0.rc3) lib/action_controller/metal.rb:236:in `block in action'
actionpack (4.2.0.rc3) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (4.2.0.rc3) lib/action_dispatch/routing/route_set.rb:42:in `serve'
actionpack (4.2.0.rc3) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.0.rc3) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.0.rc3) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.0.rc3) lib/action_dispatch/routing/route_set.rb:802:in `call'
warden (1.2.3) lib/warden/manager.rb:35:in `block in call'
warden (1.2.3) lib/warden/manager.rb:34:in `catch'
warden (1.2.3) lib/warden/manager.rb:34:in `call'
rack (1.6.0) lib/rack/etag.rb:24:in `call'
rack (1.6.0) lib/rack/conditionalget.rb:25:in `call'
rack (1.6.0) lib/rack/head.rb:13:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.0) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.0) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.0.rc3) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract/connection_pool.rb:647:in `call'
activerecord (4.2.0.rc3) lib/active_record/migration.rb:378:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:88:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:88:in `_run_callbacks'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:734:in `_run_call_callbacks'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.0.rc3) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.0.rc3) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.0.rc3) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.0.rc3) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.0.rc3) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.0.rc3) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.0) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.0) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.0.rc3) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.0) lib/rack/lock.rb:17:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/static.rb:113:in `call'
rack (1.6.0) lib/rack/sendfile.rb:113:in `call'
railties (4.2.0.rc3) lib/rails/engine.rb:518:in `call'
railties (4.2.0.rc3) lib/rails/application.rb:164:in `call'
rack (1.6.0) lib/rack/lock.rb:17:in `call'
rack (1.6.0) lib/rack/content_length.rb:15:in `call'
rack (1.6.0) lib/rack/handler/webrick.rb:89:in `service'
/Users/galli01anthony/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/httpserver.rb:138:in `service'
/Users/galli01anthony/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/httpserver.rb:94:in `run'
/Users/galli01anthony/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'

提前致谢！！！

Answer 1

我认为问题是双重的。

令牌 "values" 是标准 SQL 中的保留字。作为 insert into table_name values (...);.
使用时不带双引号，在标准 SQL 中对于用作标识符的保留字是必需的。（最好不要那样使用保留字，但仍然......） MySQL 不是标准的；它使用反引号。 SQL 服务器使用方括号。

您需要引用 values.id.

SELECT "values".* 
FROM "values" 
JOIN taggings values_taggings_5183317 
    ON values_taggings_5183317.taggable_id = "values".id 
                                          -- ^      ^
AND values_taggings_5183317.taggable_type = 'Value' 
AND values_taggings_5183317.tag_id = 2

如何获得可链接的标签？

How to Get Tags Linkable?

sql

ruby-on-rails

syntax-error

railscasts

acts-as-taggable-on