Question

以下不太有效，其目的是：

保存后，检查“运营商”中是否存在“主管”，如果没有，也将其添加。

class JobRecord(models.Model):
    """JobRecord model"""

    project             = models.ForeignKey(Project)
    date                = models.DateField()
    supervisor          = models.ForeignKey(User, related_name='supervisor_set')

    operators           = models.ManyToManyField(User, related_name='operators_set', help_text='Include the supervisor here also.')

    vehicles            = models.ManyToManyField(Vehicle, blank=True, null=True)

    def __unicode__(self):
        return u"%s - %s" % (self.project.name,  self.date.strftime('%b %d'))

    # --- over ride methods ---- #

    def save(self, **kwargs):
        # this must be done to get a pk
        super(JobRecord, self).save(**kwargs)

        # which makes this comparison possible
        if self.supervisor not in self.operators.__dict__:
            self.operators.add(self.supervisor)

        # it seems to get this far ok, but alas, the second save attempt
        # does not seem to work!
        print self.operators.values()
        super(JobRecord, self).save(**kwargs)

感谢您的专业知识，将是'专家'！

Answer 1

您可以执行以下操作来检查主管是否在运营商中：

if self.operators.filter(id=self.supervisor.id).count() == 0:

修改多对多字段后，您无需再次保存。（多对多关系存储在自己的表中。）

Answer 2

好的，我已经修改过以进行以下操作。实际上，任何条件似乎都可以解决问题。现在的问题是add（）方法对我不起作用。

#...

def save(self, **kwargs):
    super(JobRecord, self).save(**kwargs)

    if self.operators.filter(id=self.supervisor.id).count() == 0:
    #if self.supervisor not in self.operators.values():

        # either conditional will get to this point
        self.operators.add(self.supervisor) # <-- this line doesn't save proper?

Answer 3

我有同样的问题。如果您使用的是django表单，请在保存表单后进行检查，然后在那里添加多个表单。这是我能绕过它的唯一方法。

Django模型 - 在保存之前有条件地将对象添加到ManyToManyField

3 个答案: