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    <p>Your schema is incorrect. You should be making use of "Extra fields on Many-to-Many relationships" <a href="http://docs.djangoproject.com/en/dev/topics/db/models/#extra-fields-on-many-to-many-relationships" rel="nofollow noreferrer">as seen here in the Django docs</a>.</p> <p><a href="https://stackoverflow.com/questions/72945/how-to-create-a-triple-join-table-with-django">It is also highlighted here on SO.</a></p> <p><a href="http://docs.djangoproject.com/en/dev/ref/models/options/#unique-together" rel="nofollow noreferrer">Look into <code>unique_together</code></a> for your "team-number" association. I'm not sure if it will also work in conjunction with the extra fields on the many-to-many approach. Otherwise, you could enforce the uniqueness in the view, but I do believe <code>unique_together</code> should work in your case.</p> <p>For the 1-99 limitation, you should just include this in your form validation, and in conjunction with a uniqueness check, you do not need an entire table just to store the numbers 1-99.</p> <h2>Update for your edit</h2> <p>I'm not sure you actually read my post or followed any of my links but it solves exactly the problem you described, unless of course you still haven't explained the problem correctly. "Ownership" of a number is not something you should be modeling, you should be expressing it where it belongs:</p> <pre><code>class Player(models.Model): name = models.CharField(max_length=128) def __unicode__(self): return self.name class Team(models.Model): name = models.CharField(max_length=128) players = models.ManyToManyField(Player, through='Membership') def __unicode__(self): return self.name class Membership(models.Model): player = models.ForeignKey(Player) team = models.ForeignKey(Team) number = models.IntegerField() """ ... """ class Meta: unique_together = ('team', 'number') </code></pre> <p>So please explain to me again how you need an Ownership model for Player-Team-Number associations, because I'm not sure what exactly you're trying to achieve that is separate from what I already provided you.</p>
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    1. POunique value field based on another field in django
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    1. COI'm not trying to solve membership. I've updated my question with further information to hopefully clarify what I am trying to get at. Remember this is a simplified made up schema to model what I am dealing with.
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    2. COUpdated. I'm pretty sure I was already getting at exactly what you needed, pre-clarification. :)
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    3. COI think my example is poorly illustrating what I am trying to do. I appreciate your help and patience. Before I go and rip out everything I have, imagine a player can pick multiple numbers as time goes by. I think that scenario would clutter the membership table. Which is why I was trying to separate it. but I think the unique_together thing is just what I was looking for. I will play with it.
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