Rails 3.2 + ruby2 + mysql2 + NoMethodError：未定义的方法'query'为nil：NilClass
[英]Rails 3.2 + ruby2 + mysql2 + NoMethodError: undefined method `query' for nil:NilClass
问题描述
We are upgrading to 
我们正在升级到
rails version 3.2.16. rails版本3.2.16。
Mysql gem: mysql2(0.3.14) mysql gem：mysql2（0.3.14）
ruby 2.0.0p247 红宝石2.0.0p247
when i am running rake db:migrate, i'm getting below exception: 当我运行rake db：migrate时，出现以下异常：
NoMethodError: undefined method `query' for nil:NilClass: CREATE TABLE `recently_viewed_products` (`id` int(11) DEFAULT NULL auto_increment PRIMARY KEY, `gid` bigint NOT NULL, `product_id` int(11) NOT NULL, `viewed_time` int(11)) ENGINE=InnoDB/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:246:in `block in execute'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract_adapter.rb:280:in `block in log'
/usr/lib/ruby/gems/2.0.0/gems/activesupport-3.2.16/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/usr/lib/ruby/gems/2.0.0/gems/ar-octopus-0.8.0/lib/octopus/rails3/abstract_adapter.rb:19:in `instrument'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract_adapter.rb:275:in `log'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:246:in `execute'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/mysql2_adapter.rb:213:in `execute'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/schema_statements.rb:170:in `create_table'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:435:in `create_table'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:466:in `block in method_missing'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:438:in `block in say_with_time'
/usr/lib/ruby/2.0.0/benchmark.rb:281:in `measure'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:438:in `say_with_time'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:458:in `method_missing'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:334:in `method_missing'
/mnt/xxx/releases/20131218044833/db/migrate/20131202073728_create_recently_viewed_products.rb:5:in `up'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:370:in `up'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:410:in `block (2 levels) in migrate'
/usr/lib/ruby/2.0.0/benchmark.rb:281:in `measure'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:410:in `block in migrate'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/connection_pool.rb:129:in `with_connection'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:389:in `migrate'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:528:in `migrate'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:720:in `block (2 levels) in migrate'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:777:in `call'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:777:in `ddl_transaction'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:719:in `block in migrate'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:700:in `each'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:700:in `migrate'
/usr/lib/ruby/gems/2.0.0/gems/ar-octopus-0.8.0/lib/octopus/migration.rb:82:in `migrate_with_octopus'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:570:in `up'
/usr/lib/ruby/gems/2.0.0/gems/ar-octopus-0.8.0/lib/octopus/migration.rb:105:in `up_with_octopus'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/migration.rb:551:in `migrate'
/usr/lib/ruby/gems/2.0.0/gems/ar-octopus-0.8.0/lib/octopus/migration.rb:97:in `migrate_with_octopus'
/usr/lib/ruby/gems/2.0.0/gems/activerecord-3.2.16/lib/active_record/railties/databases.rake:193:in `block (2 levels) in <top (required)>'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/task.rb:236:in `call'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/task.rb:236:in `block in execute'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/task.rb:231:in `each'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/task.rb:231:in `execute'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/task.rb:175:in `block in invoke_with_call_chain'
/usr/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/task.rb:168:in `invoke_with_call_chain'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/task.rb:161:in `invoke'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:149:in `invoke_task'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:106:in `each'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:106:in `block in top_level'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:115:in `run_with_threads'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:100:in `top_level'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:78:in `block in run'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:165:in `standard_exception_handling'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/lib/rake/application.rb:75:in `run'
/usr/lib/ruby/gems/2.0.0/gems/rake-10.1.0/bin/rake:33:in `<top (required)>'
/usr/bin/rake:23:in `load'
/usr/bin/rake:23:in `<main>'
The exception is coming only when running migration for non default database. 仅当为非默认数据库运行迁移时，例外才会出现。 Here's my migration: 这是我的迁移：
ActiveRecord::Base.establish_connection("big_#{Rails.env}")
create_table :recently_viewed_products do |t|
t.integer :gid, :null => false, :limit => 8
t.integer :product_id, :null => false
t.integer :viewed_time
end
add_index :recently_viewed_products, :gid
add_index :recently_viewed_products, [:gid, :product_id], :unique=>true, :name => "UNIQUE"
ActiveRecord::Base.establish_connection(Rails.env)
Let me know if i am missing anything. 让我知道我是否想念任何东西。
1 个解决方案
解决方案1
2 2014-02-18 03:01:35
make sure you put the: 确保您输入：
ActiveRecord::Base.establish_connection YOUR_DB
line outside of the 'up' or 'change' method. 行在“向上”或“更改”方法之外。 So that it is called when the migration class is initialized rather than in the method. 这样就在初始化迁移类时（而不是在方法中）调用它。 I guess the error occurs because there hasn't been enough time for the connection to be established. 我猜是因为没有足够的时间建立连接而发生错误。
EG: 例如：
class AddBlahToBlah < ActiveRecord::Migration
ActiveRecord::Base.establish_connection "#{Rails.env}_foo"
def up
create_table ...
end
end
声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.
相关问题
Rails mysql2 undefined方法`accept'代表nil：NilClass - Rails mysql2 undefined method `accept' for nil:NilClass
ruby/sql 语法未定义方法“查询”为 nil:NilClass (NoMethodError) - ruby/sql syntax undefined method `query' for nil:NilClass (NoMethodError)
Ruby on Rails MySQL为nil：NilClass选择页面未定义方法“每个” - Ruby on Rails MySQL select page undefined method `each' for nil:NilClass
nil的未定义方法`eq'：带有rails 3的NilClass和ubuntu hardy上的ruby enterprise - undefined method `eq' for nil:NilClass with rails 3 and ruby enterprise on ubuntu hardy
移至mysql后，未定义的方法'+ @'用于nil：NilClass rails - undefined method `+@' for nil:NilClass rails after moving to mysql
Rails为nil：NilClass使用的未定义方法`email' - Rails undefined method `email' for nil:NilClass
MySQL2 / Ruby 1.9.3 / Rails上的分段错误3.2 - Segmentation Fault on MySQL2 / Ruby 1.9.3 / Rails 3.2
Rails 3.2，SQL NoMethodError：未定义方法“ auth_group =” - Rails 3.2, SQL NoMethodError: undefined method `auth_group='
nil：NilClass的未定义方法'gsub'或在rails中如何使用gsub方法 - undefined method `gsub' for nil:NilClass or how to use gsub method in rails
nil的未定义方法`code'：带有rails和遗留数据库的NilClass消息 - undefined method `code' for nil:NilClass message with rails and a legacy database
相关标签