django 复合主键(composit primary key)

class Category(models.Model):

    catid = models.CharField(max_length=50) #这里不设置主键

    bigcate = models.CharField(max_length=50) #这里不设置主键

    .........

    class Meta:

        db_table = 'my_category'

        unique_together = ("catid", "bigcate") #这是重点