django having multiple one many to many relations that references same model

Question

i have a model that is having multiple many to many relation to another model it is as follows:

class Match(models.Model):
"""Model docstring"""
   Match_Id = models.AutoField(primary_key=True)
   Team_one = models.ManyToManyField('Team',related_name='Team one',symmetrical=False,) 
   Team_two = models.ManyToManyField('Team',related_name='Team two',symmetrical=False,) 
   stadium = models.CharField(max_length=255, blank=True)
   Start_time = models.DateTimeField(auto_now_add=False, auto_now=False, blank=True, null=True)
   Rafree = models.CharField(max_length=255, blank=True)
   Judge = models.CharField(max_length=255, blank=True)
   winner = models.ForeignKey('Team', related_name='winner',to_field='Team_Name')    
   updated = models.DateTimeField('update date', auto_now=True )
   created = models.DateTimeField('creation date', auto_now_add=True )

what is the best way to implement model like this ?. all though django does not throw any errors when passing the model sql once syncdb is excuted it throws up errors saying there is no unique constraint matching given keys

Answer 1

Are you sure Team_one and Team_two should be ManyToMany fields? Surely, a match only has a single team on each side - in which case these should both be ForeignKeys.

Answer 2

Using spaces in related_name attribute makes me uneasy, but I think the real problem is connected to the use of to_field attribute on the winner field. As far as I know you can set database relations only to unique fields. It doesn't really make sense to relate to another object using a field that may not be unique.

I'm not sure what do you want to achieve by connecting through this particular field. You usually connect models using primary key fields. This still allows you to access any other field on the related object.