Rails 3，将模型中的字段从字符串更改为日期时间类型 [英] Rails 3, changing field in model from string to datetime type

问题描述

在制作模型时，我将行类型设置为字符串(当时我不知道日期时间).目前，我有很多记录已填满该行.是否有通过迁移将模型的行转换为日期时间的安全方法-除了删除它，然后再添加回去?

When making my model, I made row type as string (I wasn't aware of datetime at the time). Currently I have plenty of records that have that row filled. Is there a safe way to convert the model's row to datetime through a migration - besides just removing it, and then adding it back?

谢谢！

推荐答案

根据文档，这是一个在日期时间转换字符串的迁移示例.我不确定它是否可以正常工作，因此您可能需要先在dev/stage env上试用一下，然后再进入prod env.

Accordingly to the documentation this is an example of migration that transforms a string in datetime. I'm not sure it will work so you may want to try it out on a dev/stage env before going to the prod env.

class ChangeColumnToUsers < ActiveRecord::Migration
  def self.up
    change_column :users, :created_at, :datetime

  end

  def self.down
    change_column :users, :created_at, :string
  end
end

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