3

我有一个模型，比如说User，还有一个Admin继承自的模型User。我在lib使用这两个模型的文件夹中有一些代码。但是，如果我安装一个新数据库并尝试运行迁移 rails 崩溃说没有User. 是否有绕过此错误的最佳实践？

`Mysql2::Error: Table 'testing_interface_development.users' doesn't exist: SHOW FULL FIELDS FROM `users`
/home/arthurborisow/Programming/my_project/test_interface/lib/active_record/timed_out_queries_hotfix.rb:9:in `query'
/home/arthurborisow/Programming/my_project/test_interface/lib/active_record/timed_out_queries_hotfix.rb:9:in `query_with_reconnect'
/home/arthurborisow/Programming/my_project/test_interface/lib/active_record/timed_out_queries_hotfix.rb:31:in `block in execute'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract_adapter.rb:280:in `block in log'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activesupport-3.2.11/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract_adapter.rb:275:in `log'
/home/arthurborisow/Programming/my_project/test_interface/lib/active_record/timed_out_queries_hotfix.rb:31:in `execute'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:259:in `execute_and_free'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:426:in `columns'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/connection_adapters/schema_cache.rb:12:in `block in initialize'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:228:in `yield'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:228:in `columns'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:237:in `columns_hash'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/inheritance.rb:19:in `descends_from_active_record?'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/inheritance.rb:25:in `finder_needs_type_condition?'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/base.rb:455:in `relation'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/scoping/named.rb:37:in `scoped'
/home/arthurborisow/.rvm/gems/ruby-1.9.3-p362-railsexpress@test_interface_install/gems/activerecord-3.2.11/lib/active_record/querying.rb:9:in `where'
/home/arthurborisow/Programming/my_project/test_interface/app/models/admin.rb:15:in `<class:Admin>'
/home/arthurborisow/Programming/my_project/test_interface/app/models/admin.rb:1:in `<top (required)>'`
4

2 回答 2

3

When setting up a completely fresh database (instead of upgrading your existing one), it is better to use rake db:setup to load the schema.rb file instead of running each migration in succession. This question explains the various db Rake tasks pretty well:

Difference between rake db:migrate db:reset and db:schema:load

于 2013-04-02T06:11:01.503 回答
0 
   rake db:setup

也是最好的选择，

您还可以使用以下命令指定要迁移的迁移版本：

rake db:migrate:up VERSION=20080906120000
于 2013-04-03T18:03:23.053 回答