如何从我的 Rails 模型中删除一列? [英] How to remove a column from my Rails model?

问题描述

我需要从我已经创建的 rails 模型中删除几列，并且在该模型中有一些行条目.怎么做?任何包含在 rails 中修改架构的详细信息的链接?我使用的是 Rails 版本 3.

I need to remove a few columns from my rails model which i already created and have some row entries in that model. How to do it? Any links which has details for modifying the schema in rails ? I'm using rails version 3.

推荐答案

要删除数据库列，您必须生成迁移:

To remove a database column, you have to generate a migration:

script/rails g migration RemoveColumns

然后在 self.up 类方法中，删除您的列:

Then in the self.up class method, remove your columns:

def self.up
  remove_column :table_name, :column_name
end

您可能还想将它们重新添加到 self.down 类方法中:

You may want to add them back in the self.down class method as well:

def self.down
  add_column :table_name, :column_name, :type
end

Rails 指南对此进行了更详细的介绍.

The Rails Guide for this goes into much more detail.

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