Question

我有标准的django User model，我有一个扩展模型Member。成员模型已连接到订阅模型。

class Type(models.Model):
    limit = models.IntegerField()
    name = models.CharField(max_length=50)
    default = models.BooleanField()

    def __str__(self):
        return self.name


class Subscription(models.Model):
    started = models.DateField()
    type = models.OneToOneField(Type)

    def __str__(self):
        return self.type.name


class Member(models.Model):
    user = models.ForeignKey(to=User)
    number = models.CharField(max_length=10)
    match_code = models.CharField(max_length=50)
    parent = models.ForeignKey("self", null=True, blank=True)
    name = models.CharField(max_length=100)
    address = models.CharField(max_length=255)
    postcode = models.CharField(max_length=10)
    city = models.CharField(max_length=100)
    country = models.ForeignKey(to=Country, null=True)
    language = models.ForeignKey(to=Language)
    telephone = models.CharField(max_length=50)
    mobile = models.CharField(max_length=50)
    main_email = models.EmailField(null=True, blank=True)
    active = models.BooleanField()
    subscription = models.ForeignKey(Subscription)

    def __str__(self):
        return self.name

当我创建新用户时，以及当我想将其保存到数据库时，我按如下方式执行：

    language = Language.objects.get(key="EN")
    country = Country.objects.get(key="BE")

    # Add to user model
    user = User()
    user.username = request.POST['email']
    user.first_name = request.POST['firstname']
    user.last_name = request.POST['lastname']
    user.email = request.POST['email']
    user.set_password(request.POST['password'])
    user.save()

    # Add subscription
    subscription = Subscription()
    subscription.started = datetime.date.today()
    subscription.type = Type.objects.filter(default=True)
    last_subscription = Subscription.objects.all().order_by('-id')[0]

    # Get the last field from user model
    last_user = User.objects.all().order_by('-id')[0]
    # Add to member model with the last user
    member = Member()
    member.number = request.POST['member_id']
    member.address = request.POST['address']
    member.postcode = request.POST['postcode']
    member.city = request.POST['city']
    member.country = country
    member.telephone = request.POST['telephone']
    member.mobile = request.POST['mobile']
    member.user = last_user
    member.language = language
    member.active = False
    member.subscription = last_subscription
    member.save()

但我认为我多次访问数据库。有没有更好的解决方案呢？可以用一个查询完成吗？

Answer 1

这里有些不对劲

subscription.type = Type.objects.filter(default=True)

您将整个查询集设置为subscription.type此代码会在此处产生错误。其次，不要将默认值用作模型字段名称。

last_subscription = Subscription.objects.all().order_by('-id')[0]

不太确定你在这里想做什么。高效且无错误的方法是保存订阅对象并使用它为下一次操作生成的id。

user.username = request.POST['email']
user.first_name = request.POST['firstname']
user.last_name = request.POST['lastname']
user.email = request.POST['email']
user.set_password(request.POST['password'])

将数据直接传递给模型并不是一个好主意。您应该首先使用django表单来验证它们。

last_user = User.objects.all().order_by('-id')[0]
# Add to member model with the last user

这可能是您刚刚保存的用户，也可能不是。很可能另一个实例在此线程之后就已经保存了另一个用户。使用user.id更安全（如已经提到的关于订阅）

Answer 2

实际上，您不需要获取上次订阅或上次用户实例。您可以（而且应该！）只使用您的订阅和用户对象。因为在调用save方法后它们将具有id。"Auto-incrementing primary keys"

此外，您似乎从未保存订阅实例。

使用一个查询保存到数据库

2 个答案: