python - Django 查询关系

Question

代码没有返回基于员工的所有项目名称..？如何解决这个问题？模型有错吗？或查询？

模型.PY

class Employee(models.Model):
    name = models.CharField(max_length=100)
    telephone_number = models.CharField(max_length=20)
    address = models.TextField()
    email = models.EmailField()


class Item(models.Model):
    code = models.CharField(max_length=4)
    name = models.CharField(max_length=100)
    kind = models.CharField(max_length=100)
    description = models.TextField()


class Inventory(models.Model):
    employee = models.ForeignKey(Employee, on_delete=models.CASCADE)
    item = models.ForeignKey(Item, on_delete=models.CASCADE)

    def get_absolute_url(self):
        return reverse('inventaris-detail', kwargs={'pk': self.pk})

VIEWS.PY我怎样才能获得该员工的所有元素？

query_set = Inventory.objects.all()

    for query in query_set:
        output.append([
            query.employee.name,
            query.item.name
        ])

我需要类似query.employee.items_set.all() ..？

Answer 1

您想从员工那里获得所有元素吗？以下应该实现这一目标:

employee = Employee.objects.all()[0]  # Just get a random employee, you can do this with more employees too if you want
employees_items = [inventory.item for inventory in employee.inventory_set.all()]

老实说，您的代码在逻辑上没有多大意义。最有可能的是，Item 类上应该有一个字段，它是 Inventory 的 FK。您的元素类别可能应该是:

class Item(models.Model):
    code = models.CharField(max_length=4)
    name = models.CharField(max_length=100)
    kind = models.CharField(max_length=100)
    description = models.TextField()
    inventory = models.ForeignKey(Inventory, on_delete=models.CASCADE)

(当然这是行不通的，因为 Inventory 是在这个类之后定义的，但是你可以将 Inventory 放在它上面，或者使用其他方法之一来解决这个问题)

祝你好运!