sql server中的表似乎是在nil中放置了select语句。我不知道如何解决这个问题，如果我切换到任何其他表，我可以轻松获取第一条记录。还有其他人处理过这个bug吗？我把桌子分开并构建了一个视图。它仍然这样做。我很犹豫猴子补丁这个。想法？我是如何连接到sql server的：
我的模特：
class Deal < ActiveRecord::Base
self.table_name = 'vwStorePromosExtSummaryGlobal'
end
我的控制器：
class V1::DealsController < ApplicationController
def by_mall_id
deals = Deal.where(mallid: params[:id])
render json: deals
end
end
# Use sqlserver as the database for Active Record
gem 'tiny_tds', '~> 0.6.1'
gem 'activerecord-sqlserver-adapter', github: 'arthrex/activerecord-sqlserver-adapter'
gem 'active_model_serializers', '~> 0.8.1'
当我打开宝石中的确切错误时，我看到了：
97: def serializable_hash(options = nil)
98: options ||= {}
99:
100: attribute_names = attributes.keys
101: if only = options[:only]
102: attribute_names &= Array(only).map(&:to_s)
103: elsif except = options[:except]
104: attribute_names -= Array(except).map(&:to_s)
105: end
106:
107: hash = {}
108:
=> 109: binding.pry
110:
111: attribute_names.each { |n| hash[n] = read_attribute_for_serialization(n) }
112:
113: Array(options[:methods]).each { |m| hash[m.to_s] = send(m) if respond_to?(m) }
114:
115: serializable_add_includes(options) do |association, records, opts|
116: hash[association.to_s] = if records.respond_to?(:to_ary)
117: records.to_ary.map { |a| a.serializable_hash(opts) }
118: else
119: records.serializable_hash(opts)
120: end
121: end
122:
123: hash
124: end
[1] pry(#<Deal>)> p attribute_names.each
#<Enumerator: ["mallid", nil]:each>
=> #<Enumerator: ...>
[2] pry(#<Deal>)> p attribute_names
["mallid", nil]
=> ["mallid", nil]
[3] pry(#<Deal>)>
这是我的完整痕迹：
[1m[36mSQL (49.6ms)[0m [1mUSE [pcmenu][0m
Processing by V1::DealsController#by_mall_id as JSON
Parameters: {"id"=>"1066"}
[1m[35mDeal Load (44.5ms)[0m EXEC sp_executesql N'SELECT TOP (1) mallid FROM [StorePromosExtSummaryGlobal] WHERE [StorePromosExtSummaryGlobal].[mallid] = N''1066'' AND (salestypeid = 11
AND calcendDate > ''09-09-2013''
AND displayDate < ''09-09-2013''
AND (promoType is null or promoType = 0)) ORDER BY displayName ASC'
Completed 500 Internal Server Error in 546ms
TypeError - nil is not a symbol:
activemodel (4.0.0) lib/active_model/serialization.rb:108:in `block in serializable_hash'
activemodel (4.0.0) lib/active_model/serialization.rb:108:in `serializable_hash'
activerecord (4.0.0) lib/active_record/serialization.rb:17:in `serializable_hash'
activemodel (4.0.0) lib/active_model/serializers/json.rb:99:in `as_json'
activesupport (4.0.0) lib/active_support/json/encoding.rb:50:in `block in encode'
activesupport (4.0.0) lib/active_support/json/encoding.rb:81:in `check_for_circular_references'
activesupport (4.0.0) lib/active_support/json/encoding.rb:49:in `encode'
activesupport (4.0.0) lib/active_support/json/encoding.rb:34:in `encode'
activesupport (4.0.0) lib/active_support/core_ext/object/to_json.rb:16:in `to_json'
actionpack (4.0.0) lib/action_controller/metal/renderers.rb:90:in `block in <module:Renderers>'
active_model_serializers (0.8.1) lib/action_controller/serialization.rb:48:in `_render_option_json'
actionpack (4.0.0) lib/action_controller/metal/renderers.rb:33:in `block in _handle_render_options'
/Users/chrishough/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/set.rb:232:in `each'
actionpack (4.0.0) lib/action_controller/metal/renderers.rb:30:in `_handle_render_options'
actionpack (4.0.0) lib/action_controller/metal/renderers.rb:26:in `render_to_body'
actionpack (4.0.0) lib/abstract_controller/rendering.rb:97:in `render'
actionpack (4.0.0) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:41:in `block (2 levels) in render'
activesupport (4.0.0) lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
/Users/chrishough/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/benchmark.rb:296:in `realtime'
activesupport (4.0.0) lib/active_support/core_ext/benchmark.rb:12:in `ms'
actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:41:in `block in render'
actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:84:in `cleanup_view_runtime'
activerecord (4.0.0) lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime'
actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:40:in `render'
app/controllers/v1/deals_controller.rb:6:in `by_mall_id'
apipie-rails (0.0.22) lib/apipie/dsl_definition.rb:193:in `block in _apipie_define_validators'
actionpack (4.0.0) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (4.0.0) lib/abstract_controller/base.rb:189:in `process_action'
actionpack (4.0.0) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.0.0) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (4.0.0) lib/active_support/callbacks.rb:383:in `_run__408012802371174283__process_action__callbacks'
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.0) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (4.0.0) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.0.0) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.0.0) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.0.0) lib/active_support/notifications.rb:159:in `instrument'
actionpack (4.0.0) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.0.0) lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
activerecord (4.0.0) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.0.0) lib/abstract_controller/base.rb:136:in `process'
actionpack (4.0.0) lib/abstract_controller/rendering.rb:44:in `process'
actionpack (4.0.0) lib/action_controller/metal.rb:195:in `dispatch'
actionpack (4.0.0) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.0.0) lib/action_controller/metal.rb:231:in `block in action'
actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:80:in `dispatch'
actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:48:in `call'
actionpack (4.0.0) lib/action_dispatch/journey/router.rb:71:in `block in call'
actionpack (4.0.0) lib/action_dispatch/journey/router.rb:59:in `call'
actionpack (4.0.0) lib/action_dispatch/routing/route_set.rb:655:in `call'
apipie-rails (0.0.22) lib/apipie/static_dispatcher.rb:56:in `call'
rack (1.5.2) lib/rack/etag.rb:23:in `call'
rack (1.5.2) lib/rack/conditionalget.rb:25:in `call'
rack (1.5.2) lib/rack/head.rb:11:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/flash.rb:241:in `call'
rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.5.2) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/cookies.rb:486:in `call'
activerecord (4.0.0) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call'
activerecord (4.0.0) lib/active_record/migration.rb:369:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.0.0) lib/active_support/callbacks.rb:373:in `_run__980017763409925121__call__callbacks'
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/reloader.rb:64:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
better_errors (0.9.0) lib/better_errors/middleware.rb:84:in `protected_app_call'
better_errors (0.9.0) lib/better_errors/middleware.rb:79:in `better_errors_call'
better_errors (0.9.0) lib/better_errors/middleware.rb:56:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block in tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in `tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `tagged'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.0) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call'
railties (4.0.0) lib/rails/engine.rb:511:in `call'
railties (4.0.0) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
puma (2.5.1) lib/puma/server.rb:472:in `handle_request'
puma (2.5.1) lib/puma/server.rb:343:in `process_client'
puma (2.5.1) lib/puma/server.rb:242:in `block in run'
puma (2.5.1) lib/puma/thread_pool.rb:92:in `block in spawn_thread'
答案 0 :(得分：4)
虽然我仍然认为这是活动记录中的错误，但我能够使用https://github.com/rails-api/active_model_serializers gem来解决它。这个gem覆盖了to_json，无需调用活动记录中的bug代码。
其他人有更好的答案吗？
更新了控制器：
class V1::DealsController < ApplicationController
def by_mall_id
deals = Deal.where(mallid: params[:id]).first
render json: deals, serializer: V1::DealSerializer
end
end
我的新DealSerializer：
class V1::DealSerializer < ActiveModel::Serializer
attributes :MALLID
def MALLID
object.mallid
end
end
答案 1 :(得分：2)
这是因为您的表没有 primary_key 。您可以像这样运行迁移:(这是rails 5）
class AddFieldToPosaCode < ActiveRecord::Migration[5.0]
execute 'ALTER TABLE my_table ADD PRIMARY KEY(my_column)'
end