Rails/迁移中的模型更新

不要担心时间戳。它将自动生成。 你可以做

script\generate migration add_email_to_user email:string

This would automatically create a migration file which would look like this:

class AddEmailToUser < ActiveRecord::Migration
  def self.up
    add_column :email, :string
  end

  def self.down
    remove_column :email
  end
end

该文件将具有格式的时间戳。 YYYYMMDDHHMMSS (For Rails 2.1 and above) appended in front of the filename.

这个 Guide has information about generating migrations. If you use the rails generator, it will create correctly named files:

ruby script/generate migration AddEmailToUser email:string

Well you can do two things:

1) If you haven't deployed this anywhere yet, or you don't mind dumping the db and running your migrations again, then modify the file. 从数据库中删除表,然后运行db:migrate。Easy to do this in development.

2)如果此应用程序正在生产,或者您不想删除所有表。然后创建一个新的迁移文件。然后在这个新的迁移中添加/修改/删除列。然后运行db:migrate,新的更改将在表中生效。这是最佳实践。

至于命名迁移,使用时间戳是因为Rails将创建一个跟踪最近运行的迁移的表。为此,最好使用时间戳。但是如果您选择,您可以使用自己的约定而不是时间戳。Maybe name them 001_migration.rb, 002_migration.rb, etc.

Hope that helps.