Re: Foreign Key Chicken/Egg Inline Fu

Thanks Kurtis!

That is helpful.

-Patrick

On May 30, 1:14 pm, Kurtis Mullins <kurtis.mull...@gmail.com> wrote:
> I just checked on my own code that does something in a different
> context but kinda performs the same check. I thought I'd share it with
> you in case it helps out at all.
>
>     def clean_title(self):
>
>         # Grab the data to verify this Title is unique to this user.
>         title = self.cleaned_data['title']
>         owner = self.request.user
>         slug = slugify(title)
>
>         # Grab all user pages query for validation
>         user_pages = AbstractPage.objects.filter(owner = owner)
>         user_pages = user_pages.exclude(pk = self.instance.pk)
>
>         # Validate Uniqueness
>         if user_pages.filter(title = title).exists():
>             raise ValidationError("The page title must be unique. It appears "
>                                   + "you already have a page with this title.")
>         elif user_pages.filter(slug = slug).exists():
>             raise ValidationError("It appears that you're trying to use two "
>                                   + " pages with titles that are too similar.")
>         else: return title
>
> Of course, you'd want to 'clean' the Captain boolean field and make
> sure that no other player in the same team is a captain before
> allowing it to pass. Different context, but hopefully this approach
> can help.
>
> On Wed, May 30, 2012 at 4:05 PM, Kurtis Mullins
>
>
>
>
>
>
>
> <kurtis.mull...@gmail.com> wrote:
> > Sorry, I completely mis-read the last part of your problem. You
> > already thought about the same solution, haha. You might be able to
> > modify the Player model's clean (or save) method to prohibit any Team
> > from having more than one team captain. However, I'd probably just
> > check it in the Form you're using (outside of Admin)
>
> > On Wed, May 30, 2012 at 4:02 PM, Kurtis Mullins
> > <kurtis.mull...@gmail.com> wrote:
> >> Unless a player can play for multiple teams (which I'm doubting since
> >> Team is a ForeignKey for a Player), why not remove that 'captain'
> >> attribute from your Team and put it into your Player model as a
> >> boolean field? You could create a ModelManager or class-level model
> >> method to grab the associated team caption if you want to access it
> >> easily. Otherwise, it's just a matter of:
>
> >> Team.objects.get('team_name').player_set.filter(captain=True) # Or
> >> something along those lines...
>
> >> Just an idea anyways :) Good luck!
>
> >> On Wed, May 30, 2012 at 2:15 PM, Patrick Gavin <wezel...@gmail.com> wrote:
> >>> Hi-
>
> >>> I'm new to Django, but so far I think it is the bee's knees.
>
> >>> I could use some insight into a problem I'm working on.
>
> >>> Given the following...
>
> >>> ---------------------------------
> >>> # models.py
>
> >>> from django.db import models
>
> >>> class Team(models.Model):
> >>>    name = models.CharField(max_length=30)
>
> >>>    # captain is a player- but there can only be one captain per team.
> >>>    # null and blank are true to allow the team to be saved despite
> >>> not having a captain
> >>>    captain = models.ForeignKey('Player', related_name='team_captain',
> >>> null=True, blank=True)
>
> >>>    def __unicode__(self):
> >>>        return u'{0}'.format(self.name)
>
> >>> class Player(models.Model):
> >>>    first_name = models.CharField(max_length=20)
> >>>    last_name = models.CharField(max_length=30)
> >>>    team = models.ForeignKey('Team')
>
> >>>    def __unicode__(self):
> >>>        return u'{0} {1}'.format(self.first_name, self.last_name)
>
> >>> # admin.py
>
> >>> from league.models import *
> >>> from django.contrib import admin
>
> >>> class PlayerInline(admin.TabularInline):
> >>>    model = Player
> >>>    extra = 8
>
> >>> class TeamAdmin(admin.ModelAdmin):
> >>>    inlines = [PlayerInline]
> >>>    list_display = ('name', 'captain')
>
> >>> ---------------------------------
>
> >>> As is, when I create a new team in the admin interface I can add the
> >>> players inline, but I have to leave the team captain blank, save the
> >>> team, and then go back and change the team and set the captain to one
> >>> of the players added previously. This is kind of a drag though.
>
> >>> Is there a way that I can make the team captain be automatically set
> >>> to the first player entered inline when the team is saved the first
> >>> time?
>
> >>> I 've thought about adding a boolean field to the Player model called
> >>> "is_captain", but I want to enforce only one captain per team. If I
> >>> were to go this route, is there a way I could make the is_captain
> >>> field default to True for the first inline entry but false for the
> >>> rest?
>
> >>> Thanks,
>
> >>> -Patrick
>
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