在rails迁移中添加:on_delete到已存在的foreign_key

Question

我已经以这种方式创建了数据库中的现有外键:

class CreateUser < ActiveRecord::Migration
  def change
    create_table do ... end
    add_foreign_key :users, :admins, column: :admin_id
  end
end

但忘了添加on_delete: :nullify.迁移已被推送并用于生产.我想添加新的迁移,这将为此PK约束添加cascale删除.怎么实现呢？

Answer 1

您可以在下次迁移中删除并添加外键:

class ChangeForgeinKeyOnUsersTable < ActiveRecord::Migration[5.0]
  def change
    remove_foreign_key :users, column: :admin_id
    add_foreign_key :users, :admins, column: :admin_id, on_delete: :nullify
  end
end