获取并使用外键字段中的值，无需任何转换（Django）

发布于 2025-01-16 12:10:25 字数 1276 浏览 2 评论 0原文

我尝试从“priceWithTax()”中的外键字段“tax”获取值，最后，我可以使用下面的代码获取该值：

taxObject = self.tax

这是完整的代码：

“models.py”：

from django.db import models
from decimal import Decimal

class Tax(models.Model):
    tax = models.DecimalField(
        max_digits=3, 
        decimal_places=0,
        validators=[
            MaxValueValidator(100),
            MinValueValidator(0)
        ],
    )

class Product(models.Model):
    name = models.CharField(max_length=100)
    price = models.DecimalField(max_digits=5, decimal_places=2)

    TAX_ID = 1
    tax = models.ForeignKey(
        Tax,
        on_delete=models.PROTECT,
        default=TAX_ID,
    )

    @property
    def priceWithTax(self):
        # Here
        taxObject = self.tax
        tax = Decimal(str(taxObject))

        return round(self.price * ((tax + 100) / 100), 2)

但要使用该值，我需要先将其转换为“字符串”类型，然后再将其转换为“十进制类型”代码有点长，如下所示：

taxObject = self.tax
tax = Decimal(str(taxObject)) # Here

那么，有什么办法要使用“priceWithTax()”中外键字段“tax”的值而不进行任何转换？

原文

I tried to get the value from the foreign key field "tax" in "priceWithTax()", then finally, I could get the value with this code below:

taxObject = self.tax

This is the full code:

"models.py":

from django.db import models
from decimal import Decimal

class Tax(models.Model):
    tax = models.DecimalField(
        max_digits=3, 
        decimal_places=0,
        validators=[
            MaxValueValidator(100),
            MinValueValidator(0)
        ],
    )

class Product(models.Model):
    name = models.CharField(max_length=100)
    price = models.DecimalField(max_digits=5, decimal_places=2)

    TAX_ID = 1
    tax = models.ForeignKey(
        Tax,
        on_delete=models.PROTECT,
        default=TAX_ID,
    )

    @property
    def priceWithTax(self):
        # Here
        taxObject = self.tax
        tax = Decimal(str(taxObject))

        return round(self.price * ((tax + 100) / 100), 2)

But to use the value, I needed to convert it to "String" type first and then "Decimal type" next which became a little bit long code as shown below:

taxObject = self.tax
tax = Decimal(str(taxObject)) # Here

So, are there any ways to use the value from the foreign key field "tax" in "priceWithTax()" without any conversions?

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稀香 2025-01-23 12:10:25

是的，您可以使用“priceWithTax()”中外键字段“tax”的值，无需任何转换。

因此，替换此代码：

taxObject = self.tax
tax = Decimal(str(taxObject))

使用此代码：

tax = self.tax.tax

这是完整的代码：

"models.py"：

from django.db import models
from decimal import Decimal

class Tax(models.Model):
    tax = models.DecimalField(
        max_digits=3, 
        decimal_places=0,
        validators=[
            MaxValueValidator(100),
            MinValueValidator(0)
        ],
    )

class Product(models.Model):
    name = models.CharField(max_length=100)
    price = models.DecimalField(max_digits=5, decimal_places=2)

    TAX_ID = 1
    tax = models.ForeignKey(
        Tax,
        on_delete=models.PROTECT,
        default=TAX_ID,
    )

    @property
    def priceWithTax(self):
        # Here
        tax = self.tax.tax        
        return round(self.price * ((tax + 100) / 100), 2)

Yes, you can use the value from the foreign key field "tax" in "priceWithTax()" without any conversions.

So, replace this code:

taxObject = self.tax
tax = Decimal(str(taxObject))

With this code:

tax = self.tax.tax

This is the full code:

"models.py":

from django.db import models
from decimal import Decimal

class Tax(models.Model):
    tax = models.DecimalField(
        max_digits=3, 
        decimal_places=0,
        validators=[
            MaxValueValidator(100),
            MinValueValidator(0)
        ],
    )

class Product(models.Model):
    name = models.CharField(max_length=100)
    price = models.DecimalField(max_digits=5, decimal_places=2)

    TAX_ID = 1
    tax = models.ForeignKey(
        Tax,
        on_delete=models.PROTECT,
        default=TAX_ID,
    )

    @property
    def priceWithTax(self):
        # Here
        tax = self.tax.tax        
        return round(self.price * ((tax + 100) / 100), 2)

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