将数据库列类型更改为十进制 [英] Change database column type to decimal

问题描述

我正在将Rails 3.2.3和MySQL用于我的数据库


我创建了一个名为affiliate_payment.rb的模型，其列为：amount ，最初的数据类型为 float 。我尝试通过以下迁移将其更改为十进制：

I am using Rails 3.2.3, and MySQL for my database
I have created a model affiliate_payment.rb, with a column :amount, initially with datatype float. I tried to change this to a decimal with the following migration:

class ChangeAffiliateIdAmountToDecimal < ActiveRecord::Migration
  def up
    change_column :affiliate_payments, :amount, :decimal
  end

  def down
    change_column :affiliate_payments, :amount, :float
  end
end

Ran rake db：迁移 ...
但是当我检查列类型进行确认时，我发现列类型现在为整数！

Ran rake db:migrate...
But when I check the column type to confirm, I find that the column type is now integer!

2.0.0-p353 :101 > AffiliatePayment.columns_hash["amount"].type
 => :integer 

有人可以解释我在做什么错吗？

Can someone explain what I am doing wrong?

推荐答案

尝试一下：

change_column :affiliate_payments, :amount, :decimal, :precision => 8, :scale => 2

这将成为 BigDecimal

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