如何格式化此PostgreSQL查询以使其能够使用db:migrate运行

Question

我想创建下面的表。我是通过从ActiveRecord运行SQL来实现的。

alter table items add column sumup numeric generated always as ( quantity * price + (quantity * price* fpa/100) ) stored;

这是正确的做法吗？

  def change
    create_table :items do |t|
      t.string :itemName
      t.string :prom
      t.string :promCode
      t.string :baseCode
      t.string :desc
      t.numeric :fpa
      t.numeric :price
      t.integer :quantity
      t.string :monadaMe
      t.string :familys

      t.timestamps
    end
    ActiveRecord::Base.connection.execute(" alter table items add column sumup numeric generated always as ( quantity * price + (quantity * price* fpa/100) ) stored;")
  end
end

Answer 1

仅创建新列：

rails generate migration AddSumupToItems sumup:float

在您的model中，添加：

before_save :calculate_sumup

def calculate_sumup
  sumup = ( quantity * price + (quantity * price* fpa/100) )
  self.sumup = sumup
end