Question

我想用计算字段保存django模型，以便我可以对其进行搜索。

class TestModel(models.Model):
    x = models.CharField(max_length=16)
    z = models.CharField(max_length=16)

    # I want a field like below and also saves in databse
    # computed =  computed()

    def computed(self):
        result = self.x + self.y
        return result

Answer 1

class TestModel(models.Model):
    x = models.CharField(max_length=16)
    z = models.CharField(max_length=16)
    computed = models.CharField(max_length=32, editable=False)

    def save(self, *args, **kwargs):
        self.computed = self.x + self.y
        super(TestModel, self).save(*args, **kwargs)

Here是editable选项的作用。 More

Answer 2

我们应该覆盖save（）方法。

class TestModel(models.Model):
    x = models.CharField(max_length=16)
    z = models.CharField(max_length=16)
    computed =  models.CharField(max_length=32)

    def get_computed(self):
        result = self.x + self.y
        return result

    def save(self, *args. **kwargs):
        self.computed = self.get_computed()
        super(TestModel, self).save(*args, **kwargs)

Answer 3

首先，您必须拥有计算的＆＃39; TestModel中定义的字段。然后，当您创建新的TestModel记录时，您可以在创建记录期间计算x + y并保存它。

TestModel.objects.create(x=x_value, y=y_value, computed=(x_value + y_value))

这应该这样做。

Django-model：在模型字段中保存计算值

3 个答案: