Hi Ramiro,
Thank you for the response. I read the links and modified my model
files as you instructed. I am currently able to loop through
scientists that belong to a conference and print them out. However, I
also need to be able to loop through conferences that a scientist is
attending. I am not able to do that with the solution that you
provided.
------ myproject.scientist.views -----
def portal
s = get_object_or_404(Scientist, pk=scientist_id)
----- templates/portal.html
{% for conference in scientist.conference.all %}
<a href="/">{{ conference.title }}</a>,
{% endfor %}
On Apr 5, 11:19 am, Ramiro Morales <cra...@gmail.com> wrote:
> On Sun, Apr 5, 2009 at 11:43 AM, codecowboy <guy.ja...@gmail.com> wrote:
>
> > Hi Everyone,
>
> > I'm new to the Django community and I am having trouble with circular
> > imports. I've read every article that I can find about the issue
> > including posts on this group. I'm going to paste my model files and
> > the stack trace. I'm sure that this must be an issue that has come up
> > before. Thank you in advance for any help. If you know of an article
> > that explains the problem then point me to it. Thanks again.
>
> > [snip]
>
> Do you need to have two, parallel, many to many relationships between
> Scientist
> and Conference?. If the answer is no then yo don't need to define that
> relationship in both models. This alone almost solves your circular reference
> problem.
>
> The technique of using a string with the name of the model instead of tthe
> Model
> class onject iself to indicate the target of a relationship is only needed
> (and
> accepted) when:
>
> * The target model hasn't yet been defined (It comes after in the same
> application models.py file).
>
> * or when you have two mutually referencing relationships between
> two models located in diferent applications (actually, this second use case
> isn't clearly explained in our documentation)
>
> Using these guidelines and simplifying you example to the relevant bits,
> something like this could be a start of a solution to your problem:
>
> ------ scinet.scientists.models -----------
> from django.db import models
>
> class Scientist(models.Model):
> # ...
> # no many to many field needed here
>
> ------ scinet.conferences.models -----------
> from django.db import models
> from scinet.scientists.models import Scientist
>
> class ConferenceAttendee(models.Model):
> # ...
> conference = models.ForeignKey('Conference')
> scientist = models.ForeignKey(Scientist)
>
> class Conference(models.Model):
> # ...
> scientists = models.ManyToManyField(Scientist, through=ConferenceAttendee)
>
> Relevant documentation links worth reading:
>
> http://docs.djangoproject.com/en/dev/topics/db/models/#many-to-many-r...http://docs.djangoproject.com/en/dev/topics/db/models/#models-across-...http://docs.djangoproject.com/en/dev/ref/models/fields/#lazy-relation...
>
> HTH
>
> --
> Ramiro Moraleshttp://rmorales.net
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