Rake 迁移找不到表答案

【问题标题】：Rake migration cannot find the tableRake 迁移找不到表
【发布时间】：2013-01-30 20:38:55
【问题描述】：

所以我在 db->migrate 文件夹中创建了一个手动文件名 001_create_users.rb，如下所示：

class CreateUsers < ActiveRecord::Base
  def self.up
    create_table :users do |t|
      t.string :name
      t.string :email
      t.string :password
      t.string :bio

      t.timestamps
    end
  end

  def self.down
    drop_table :users
  end
end

然后我运行一个 :bundle exec rake db:migrate 命令，我得到这个错误：

rake 中止！发生错误，此迁移和所有后续迁移取消：

找不到表'create_users'

错误是更多细节，所以我只是从终端窗口复制粘贴它，但第一部分是我得到的错误的头部

rake 中止！发生错误，此迁移和所有后续迁移取消：

找不到表“create_users” /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/connection_adapters/sqlite_adapter.rb:472:in table_structure' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/connection_adapters/sqlite_adapter.rb:346:incolumns' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/connection_adapters/schema_cache.rb:12:in block in initialize' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:228:inyield' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:228:in default' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:228:incolumns' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:243:in column_defaults' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/base.rb:482:ininitialize' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:538:in new' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:538:inload_migration' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:533:in migration' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:528:inmigrate' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:720:in block (2 levels) in migrate' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:incall' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:in block in ddl_transaction' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/database_statements.rb:192:intransaction' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/transactions.rb:208:in transaction' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:inddl_transaction' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:719:in block in migrate' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:700:ineach' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:700:in migrate' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:570:inup' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/gems/activerecord-3.2.11/lib/active_record/migration.rb:551:in migrate' /Users/JonyIve/Documents/HisFirstService/Rakefile:19:inblock (2 级) in ' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/bin/ruby_noexec_wrapper:14:in eval' /Users/JonyIve/.rvm/gems/ruby-1.9.3-p362@railsbabak/bin/ruby_noexec_wrapper:14:in' 任务：TOP => db:migrate（通过运行任务查看完整跟踪 --trace)

另外，如果我说“哪个宝石”，这就是我得到的：

which gem
/Users/JonyIve/.rvm/rubies/ruby-1.9.3-p362/bin/gem

【问题讨论】：

标签： ruby-on-rails rake rails-migrations

【解决方案1】：

你是从ActiveRecord::Base继承的，而它应该是ActiveRecord::Migration。

class CreateProjects < ActiveRecord::Migration
  def change
    create_table :projects do |t|
      t.text :title
      t.text :description
      t.text :slug

      t.timestamps
    end
  end
end

【讨论】：