python - 将对象添加到 ManyToManyField 时，Django 如何填充 'trough' 中间模型中的字段？

Question

我无法正确表达它，也无法在文档中找到它，但是在向 ManyToManyField 添加新对象时，如何将其添加到中间“通过”模型？

请注意，它是一种递归关系，但我使用了ManyToMany，因为我不确定OneToOne是否支持“通过”模型(文档没有指定它)

此外，无论 curr_partner 字段如何，都将使用 Person_Person，向其添加诸如 parent /子女关系之类的对象(在 Person 中没有字段) ) (这是由于混淆了 ManyToManyField 是 SQL 关系数据库中输出表中的实际字段)

(我意识到我的模型存在一些上下文/理论缺陷，但现在让我们抽象一下)

例如

模型.py:

class Person(models.Model):
    objectid = models.AutoField(primary_key=True)
    name = models.CharField()
    curr_partner = models.ManyToManyField(
        self, 
        on_delete = models.CASCADE, 
        through = Person_Person, #This lets you define the model that will act as an intermadiary
        symmetrical = False, #This needs to be set with recursive relationships
    )

class Person_Person(models.Model):
    person_1 = models.ForeignKey(Person, ondelete=models.CASCADE)
    person_2 = models.ForeignKey(Person, ondelete=models.CASCADE)
    relation = models.ChoiceField(            
        ('P', 'Parent'),
        ('C', 'Child'),
        ('E', 'Engaged'),
        ('W', 'Widow'),
    )

查询:

#Adding a married couple

father = Person(name = "John")
mother = Person(name = "Anna")

father.curr_partner.add( mother , through.relation = "Engaged") #???

#Adding a 'Child' relation

child = Person(name = "Billy")

#This makes sense??
p1 = Person_Person(person1 = father, person2 = child, relation = "Child")
p2 = Person_Person(person1 = mother, person2 = child, relation = "Child")

Answer 1

您通过保存关系模型的实例来创建关系，就像您(几乎)对 child 所做的那样。你会有类似的东西

father = Person(name = "John")
mother = Person(name = "Anna")

marriage = Person_Person.objects.create(person1=father, person2=mother, relation="E")

p1 = Person_Person.objects.create(person1=father, person2=child, relation="C")
p2 = Person_Person.objects.create(person1 = mother, person2 = child, relation="C")

顺便说一句，您的 curr_partner 属性没有准确的名称，因为它实际上表示一个人的所有关系，而不仅仅是婚姻。也许您应该将其重命名为 relationships 或 kindred 并拥有一个属性来获取此人的伴侣:

@property
def curr_partner(self):
    try:
        return self.relationships.objects.get(relation='E')
    except Person_Person.DoesNotExist:
        # No marriage relationship
        return