Rails 迁移 - 未定义的方法`'

Question

我们正在尝试将 DB 的列重命名为 rails 约定：

class MakeRailsy < ActiveRecord::Migration
  def change
    # Classes
    rename_table :Classes, :classes_
    rename_table :classes_, :classes
    rename_column :classes, :ClassID, :id
    rename_column :classes, :ClassNO, :class_no
    rename_column :classes, :SE,      :se
    rename_column :classes, :EE,      :ee
    rename_column :classes, :CE,      :ce
    rename_column :classes, :MBA,     :mba
    rename_column :classes, :CS,      :cs
    rename_column :classes, :AM,      :am
    rename_column :classes, :ESL,     :esl
    rename_column :classes, :U_G,     :u_g

    %w(ClassName DepartmentID SectionNumber InstructorID Units Location 
       DaysAndTimes Notes Description).each do |column|
      rename_column :classes, column, column.underscore
    end

但这会引发错误：

-- rename_column(:classes, "ClassName", "class_name")
   -> 0.0089s
--  ([])
rake aborted!
StandardError: An error has occurred, all later migrations canceled:
undefined method ` ' for #<MakeRailsy:0x007ffa718e1160>/Users/kellyprice/git/transcript_archives/db/migrate/20150401225004_make_railsy.rb:19:in `block in change'    
/Users/kellyprice/git/transcript_archives/db/migrate/20150401225004_make_railsy.rb:18:in `each'
/Users/kellyprice/git/transcript_archives/db/migrate/20150401225004_make_railsy.rb:18:in `change'
NoMethodError: undefined method ` ' for #<MakeRailsy:0x007ffa718e1160>
/Users/kellyprice/git/transcript_archives/db/migrate/20150401225004_make_railsy.rb:19:in `block in change'
/Users/kellyprice/git/transcript_archives/db/migrate/2015040122500

尝试排除 scope/syntax 个错误我试过了，但无济于事：

self.rename_column(:classes, column, column.underscore)

而且，如果您拉平循环并手动调用 rename_column，它似乎可以工作。

Answer 1

您的文件中有一个 unicode space，Ruby 已将其确定为方法调用。这是其中之一：http://www.fileformat.info/info/unicode/char/2002/index.htm

如果您从错误消息中复制 space 并搜索替换为常规 space，我认为应该可以修复它。

Answer 2

在那个循环中似乎有复制和粘贴 en space。

快速搜索和替换：

:%s/ / /g

Rails 迁移 - 未定义的方法`'

Rails migration - undefined method ` '

ruby-on-rails

rails-migrations