Re: How to use primary key as an attribute

If I understand what you are building. You want some way to group
messages into threads? I assume that a Thread will have many messages?
Unless I am missing something you might want something like this:

class Thread(models.Model):
subject = models.CharField(max_length=256)

class Message(models.Model):
thread = models.ForeignKey(Thread)
sent_date = models.DateTimeField(default=datetime.now)
body = models.TextField()
user = models.ForeignKey(User)

Then you can create a filter for the Thread based on a subject:

selected_subject = Thread.objects.filter(subject="some subject")

Then when you create the message you can use thread =
selected_subject[0] (assuming unique subjects/threads) when you create
your message. OR if 'some subject' isn't found, len(selected_subject)
== 0 then create a new Thread.

HTH,
Tim



On Sun, Dec 1, 2013 at 8:30 AM, Aamu Padi <aamupadi@gmail.com> wrote:
> Actually I need to use Thread class in other class as a ForeignKey. Here is
> the whole code:
>
> class Thread(models.Model):
> thread_pk = models.PositiveIntegerField(default=self.pk)
>
> class ThreadParticipant(models.Model):
> thread = models.ForeignKey(Thread)
> user = models.ForeignKey(User)
>
> class Message(models.Model):
> thread = models.ForeignKey(Thread)
> sent_date = models.DateTimeField(default=datetime.now)
> body = models.TextField()
> user = models.ForeignKey(User)
>
>
> Is there anyway to create a new message without manually creating a Thread.
> I mean to auto-populate the Thread, whenever I create a new Message?
>
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