运行数据库迁移时未定义的方法 "each_pair" 出错

Question

这里是错误：

迁移代码：

class Test < ActiveRecord::Migration
  def change
    create_table :test do |t|
    end
  end
end

附带说明一下，如果我删除 "Create_table" 调用，它不会失败。

运行 rake db:migrate 后，我收到此错误消息：

StandardError: An error has occurred, this and all later migrations canceled:

undefined method `each_pair' for []:Array/Users/m/Apps/stream-web/db/migrate/20150329070040_test.rb:3:in `change'
NoMethodError: undefined method `each_pair' for []:Array
/Users/m/Apps/stream-web/db/migrate/20150329070040_test.rb:3:in `change'

如何解决这个问题？我正在使用 "pg" gem，我的适配器是 postgresql。

完整跟踪错误：

undefined method `each_pair' for []:Array/Users/mingyeowng/.rbenv/versions/2.1.5/lib/ruby/gems/2.1.0/gems/activerecord-4.2.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:216:in `create_table'
/Users/mingyeowng/.rbenv/versions/2.1.5/lib/ruby/gems/2.1.0/gems/schema_plus-1.8.5/lib/schema_plus/active_record/connection_adapters/schema_statements.rb:39:in `create_table_with_schema_plus'
/Users/mingyeowng/.rbenv/versions/2.1.5/lib/ruby/gems/2.1.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:662:in `block in method_missing'
/Users/mingyeowng/.rbenv/versions/2.1.5/lib/ruby/gems/2.1.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:632:in `block in say_with_time'
/Users/mingyeowng/.rbenv/versions/2.1.5/lib/ruby/2.1.0/benchmark.rb:279:in `measure'
/Users/mingyeowng/.rbenv/versions/2.1.5/lib/ruby/gems/2.1.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:632:in `say_with_time'
/Users/mingyeowng/.rbenv/versions/2.1.5/lib/ruby/gems/2.1.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:652:in `method_missing'
/Users/mingyeowng/Apps/stream-web/db/migrate/20150329070040_test.rb:3:in `change'

Answer 1

这取决于您正在使用的 schema_plus gem：rails 4.2.1 更改了它正在覆盖的方法的签名。

gem的1.x系列有一个fix on the master branch, however this won't be backported，不支持rails4.2以后的版本。但是，您可以使用当前的 2.0.0 预发布版本。

运行数据库迁移时未定义的方法 "each_pair" 出错

Undefined Method "each_pair" Error when running DB Migrate

activerecord

ruby-on-rails

dbmigrate

运行 数据库迁移时未定义的方法 "each_pair" 出错

Undefined Method "each_pair" Error when running DB Migrate

activerecord

ruby-on-rails

dbmigrate

运行数据库迁移时未定义的方法 "each_pair" 出错