Ruby rails的耙子不能回滚得足够远
我尝试“rake db：rollback STEP = 6”或更多，但是当我运行“rake db：migrate”时，它只显示正在执行的最后一个迁移文件：
== 20150508040222 CreateStructure：迁移================================== == 20150508040222 CreateStructure：迁移（0.0000s） =========================
当我尝试使用“rails console”和“puts User.new（）。检查”来检查是否在上一步中创建了新字段时，它显示这些字段仍然缺失。
如何回滚以便它将执行我编辑的交易文件？
[编辑]
当我使用“rake db：migrate VERSION = 20150328013052”尝试回滚时，它在第二次迁移时失败，因为它无法删除不存在的字段。 我认为我修改了迁移以在迁移完成后添加这些字段，因此这些字段不存在。 我该怎么办？ 我尝试修改schema.rb中的时间戳并运行迁移，但看起来这不是跟踪当前版本的内容。
class AddLoginToUsers < ActiveRecord::Migration
def change
add_column :name, :password, :string
end
end
== 20150508040222 CreateStructure：恢复================================== == 20150508040222 CreateStructure：恢复（0.0273s） =========================
== 20150506210153 AddLoginToUsers：恢复================================== - remove_column（：name，：password， ：字符串）耙中止！ StandardError：发生错误，已取消此次及以后的所有迁移：
无法找到表'name'/ var / lib / gems / 1.9.1 / gems / activerecord-4.2.0 / lib / active_record / connection_adapters / sqlite3_adapter.rb：517：在table_structure' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/sqlite3_adapter.rb:431:in /var/lib/gems/ table_structure' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/sqlite3_adapter.rb:431:in primary_key' table_structure' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/sqlite3_adapter.rb:431:in sqlite3_adapter.rb：538：in copy_table' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/sqlite3_adapter.rb:533:in '/var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/sqlite3_adapter.rb: copy_table' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/sqlite3_adapter.rb:533:in :in copy_table' 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/var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:652:in : say_with_time' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:652:in :in method_missing'/ say_with_time' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:652:in activerecord-4.2.0 / lib / active_record / migration.rb：497：在block in revert' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:496:in每个'/var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:496:在revert' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:604:in exec_migration' revert' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:604:in 590 revert' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:604:in block (2 levels) in migrate' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/migration.rb:589:in lib/ block (2 levels) in migrate' 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：在execute_migration_in_transaction中的块'/var/lib/gems/1.9.1/gems /activerecord-4.2.0/lib/active_record/migration.rb:1041:in ddl_transaction中的block in ddl_transaction' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in事务block in ddl_transaction' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in块中/var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/abstract/transaction.rb:188:in within_new_transaction' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in transaction'/ within_new_transaction' /var/lib/gems/1.9.1/gems/activerecord-4.2.0/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in ems / activerecord-4.2.0 / lib / active_record / transactions.rb：220：in transaction' 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[编辑]
好的，我明白了，我只需要清除迁移就可以撤消它们，并重新编写它们。 问题解决了。
我会通过打开schema.rb文件（位于db / schema.rb）中找到Schema的当前状态，第一行看起来像这样：
ActiveRecord::Schema.define(version: 20150507210038) do
将该版本号与db / migrate文件夹中的迁移进行匹配。 也许你已经在适当的迁移。 要回去迁移，我建议：
rake db:migrate VERSION=20080906120000
版本号与迁移文件名称上的版本相对应。
[UPDATE]
错误在这里：
class AddLoginToUsers < ActiveRecord::Migration
def change
add_column :name, :password, :string
end
end
add_column具有以下要求：
add_column :table, :column_name, :column_type
确保桌子是多元化的。 检查您的Schema.rb文件以查看表格。 既然这是用户表，也许你的意思是这样的：
add_column :users, :password, :string
如果您在架构方面存在问题，则可以完全转储数据库并重新创建它。 我将编辑适当的迁移（删除引起问题的迁移），然后运行以下命令转储并重新创建数据库：
rake db:drop db:create db:migrate
然后，您可以运行其他迁移以添加新列。 您可以将这些添加到现有的迁移中，然后重新创建数据库。 希望有所帮助。
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