Django为字段设置手动算术公式 [英] Django set manual arithmetic formula for a field

问题描述

我想设置模型中字段的手动算术公式，该公式在模型的对象之间变化，并由某些用户设置，并根据外部模型名称进行设置。

I want to set manual arithmetic formula of a field in a model, the formula changes from object to object of the model and is set by some user and sets it depending on the foreign model name.

例如：

model B:
name =char

model A:  
field 1 = int  
field 2 = int 
field 3 = foreign(model B)
field 4 = set formula

在模型A的对象1中，管理员将字段4 =字段1 +字段2设置为字段3 = x

In object 1 of model A, Admin sets field4 = field1 + field2 if field 3 = "x" from admin portal

在模型A的对象2中，如果
字段3 = y，则管理员从管理门户设置field4 = field1 * field2

In object 2 of model A, Admin sets field4 = field1 * field2 if field 3 = "y" from admin portal

在Django中可能吗？

Is this possible in Django?

实际上，我正在尝试将Excel工作表数据转换为Django应用程序给定选项卡的表（这里是模型A），我将有一些固定的列（这里是模型B），但是有一列，我将根据选项卡名称设置列的算术公式。
现在在我的Django应用程序中，基于模型A的名称，我需要能够为模型B设置公式。

Actually, I am trying to convert my excel sheet data into Django application, in my excel sheet for a given tab (here model A) I will have some fixed columns (here model B) but there is a column for which I will set the arithmetic formula of columns based on the tab name. Now in my Django application based on the name of model A, I need to be able to set a formula for model B.

什么是最好的方法

推荐答案

Django是否提供内置函数来实现此目的？

Does Django provide builtin functions to achieve this? No.

可以自定义Django来实现吗？是的。

Can you customize Django achieve this? Yes.

import operator
operator_map = {"+": operator.add, "-":operator.sub...}
class ModelB:
    _operator <- while will store a raw operator
    @property
    def operator(self):
        return operator_map[self._operator]

如果运算符将是动态的。 将运算符函数存储为另一列并存储在您的媒体资源中

If the operator is going to be dynamic. Store the operator function as another column and in your property

class Model
    @property
    def field4(self):
        return self.field3.operator(self.field1, self.field2)

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