将已删除列中的数据移动到Rails迁移中刚刚创建的数据

Question

我有一个表'Invoices',其中包含两个布尔列:

Table name: invoices

id               :integer          not null, primary key
...
sent             :boolean          default(FALSE)
payment_received :boolean          default(FALSE)

这两列定义了发票的状态:

def status
  if sent & payment_received
    :paid
  elsif sent | payment_received
    :sent
  else
    :created
  end
end

有一天,我们决定删除这些布尔列,并在Rails枚举的帮助下创建包含发票状态的新列

status :integer

enum status: [ :created, :sent, :paid ]

所以现在我需要做三件事:

1. 添加新列"状态"
2. 计算现有发票的状态,更新状态列
3. 删除列'sent'和'payment_received'.

我怎样才能做到这一点？我可以在我的本地环境中轻松完成此任务,但我无法理解如何在生产服务器上执行此操作.例如,如果我将创建一个更新我的表的迁移和一个计算状态的rake任务,则迁移首先传递,我的数据将从布尔列中移除,然后才能使用它们.

注意:如果它以某种方式重要:我使用Postgres.

任何帮助表示赞赏!

Answer 1

请尝试以下迁移.

class UpdateInvoicesTable < ActiveRecord::Migration
  def self.up
    add_column :invoices,:status,:string

    Invoice.find_in_batches(batch_size: 2000) do |invoices|
      invoices.each do |invoice|
        if invoice.sent & invoice.payment_received
          invoice.status = 'paid'
        elsif invoice.sent | invoice.payment_received
          invoice.status = 'sent'
        else
          invoice.status = 'created'
        end
        invoice.save
      end
    end

    remove_column :invoices,:sent
    remove_column :invoices,:payment_received
  end  
end