Django两个多对多字段一个关联表

Question

我想创建一个有两个manytomanyfield的模型。我不希望Django创建两个关联表，而是为manytomanyfield创建同一个关联表。

这是我的模型:

class Tab(WModel):
    forms = models.ManyToManyField('Form', null=True, blank=True)
    fields = models.ManyToManyField('Field', null=True, blank=True)
    number = models.IntegerField(null=True, blank=True)
    class Meta:
        db_table = 'tab'

我只想创建这个关联表:

tab_assoc :
   id_tab
   id_form
   id_field
   number

Answer 1

class Field(models.Model):
    name = models.CharField(max_length=128)
    def __str__(self):              # __unicode__ on Python 2
        return self.name
class Form(models.Model):
    name = models.CharField(max_length=128)
    fields = models.ManyToManyField(Field, through='Tab')
    def __str__(self):              # __unicode__ on Python 2
        return self.name
class Tab(models.Model):
    field = models.ForeignKey(Field)
    form = models.ForeignKey(Form)