Abordagem evitando o relacionamento ternário.

models_exp.py

"""
>>> rsp = models.Journal.objects.create(title=u'Revista de saúde pública')
(0.002) INSERT INTO "journalmanager_journal" ("title") VALUES (Revista de saúde pública); args=[u'Revista de sa\xfade p\xfablica']
>>>
>>> brasil = models.Collection.objects.create(name=u'Brasil')
(0.001) INSERT INTO "journalmanager_collection" ("name") VALUES (Brasil); args=[u'Brasil']
>>>
>>> rsp.join(brasil)
(0.001) INSERT INTO "journalmanager_membership" ("journal_id", "collection_id", "publication_status", "publication_status_since") VALUES (1, 1, c, 2014-03-22 22:47:59.174742); args=[1, 1, 'c', u'2014-03-22 22:47:59.174742']
(0.001) INSERT INTO "journalmanager_journaltimeline" ("journal_id", "collection_id", "publication_status", "publication_status_since") VALUES (1, 1, c, 2014-03-22 22:47:59.174742); args=[1, 1, 'c', u'2014-03-22 22:47:59.174742']
>>>
>>> rsp.change_status(brasil, 'd')
(0.000) SELECT "journalmanager_membership"."id", "journalmanager_membership"."journal_id", "journalmanager_membership"."collection_id", "journalmanager_membership"."publication_status", "journalmanager_membership"."publication_status_since" FROM "journalmanager_membership" WHERE ("journalmanager_membership"."journal_id" = 1  AND "journalmanager_membership"."collection_id" = 1 ); args=(1, 1)
(0.000) SELECT (1) AS "a" FROM "journalmanager_membership" WHERE "journalmanager_membership"."id" = 1  LIMIT 1; args=(1,)
(0.001) UPDATE "journalmanager_membership" SET "journal_id" = 1, "collection_id" = 1, "publication_status" = d, "publication_status_since" = 2014-03-22 22:48:15.571127 WHERE "journalmanager_membership"."id" = 1 ; args=(1, 1, 'd', u'2014-03-22 22:48:15.571127', 1)
(0.000) SELECT "journalmanager_journal"."id", "journalmanager_journal"."title" FROM "journalmanager_journal" WHERE "journalmanager_journal"."id" = 1 ; args=(1,)
(0.000) SELECT "journalmanager_collection"."id", "journalmanager_collection"."name" FROM "journalmanager_collection" WHERE "journalmanager_collection"."id" = 1 ; args=(1,)
(0.000) INSERT INTO "journalmanager_journaltimeline" ("journal_id", "collection_id", "publication_status", "publication_status_since") VALUES (1, 1, d, 2014-03-22 22:48:15.571127); args=[1, 1, 'd', u'2014-03-22 22:48:15.571127']
>>>
>>> rsp.membership_info(brasil, 'publication_status')
(0.000) SELECT "journalmanager_membership"."id", "journalmanager_membership"."journal_id", "journalmanager_membership"."collection_id", "journalmanager_membership"."publication_status", "journalmanager_membership"."publication_status_since" FROM "journalmanager_membership" WHERE ("journalmanager_membership"."journal_id" = 1  AND "journalmanager_membership"."collection_id" = 1 ); args=(1, 1)
u'd'
>>>
>>> rsp.statuses.all()
(0.000) SELECT "journalmanager_journaltimeline"."id", "journalmanager_journaltimeline"."journal_id", "journalmanager_journaltimeline"."collection_id", "journalmanager_journaltimeline"."publication_status", "journalmanager_journaltimeline"."publication_status_since" FROM "journalmanager_journaltimeline" WHERE "journalmanager_journaltimeline"."journal_id" = 1  LIMIT 21; args=(1,)
[<JournalTimeline: JournalTimeline object>, <JournalTimeline: JournalTimeline object>]
"""
from django.db import models


class Journal(models.Model):
    collections = models.ManyToManyField('Collection',
        through='Membership', related_name='journals')
    title = models.CharField(max_length=32)

    def join(self, collection):
        """Make this journal part of the collection.
        """

        Membership.objects.create(journal=self,
                                  collection=collection,
                                  publication_status='c')

    def membership_info(self, collection, attribute=None):
        """Retrieve info about the relation of this journal with a
        given collection.
        """
        rel = self.membership_set.get(collection=collection)
        if attribute:
            return getattr(rel, attribute)
        else:
            return rel

    def change_status(self, collection, new_status):
        rel = self.membership_info(collection)
        rel.publication_status = new_status
        rel.save()


class Collection(models.Model):
    name = models.CharField(max_length=32)

    def add_journal(self, journal):
        journal.join(self)


class Membership(models.Model):
    """
    Represents the many-to-many relation
    between Journal and Collection.
    """
    journal = models.ForeignKey('Journal')
    collection = models.ForeignKey('Collection')

    publication_status = models.CharField(max_length=1,
        choices=[('c', 'current'), ('d', 'deceased')])
    publication_status_since = models.DateTimeField(auto_now=True)

    def save(self, *args, **kwargs):
        """
        Always save a copy at JournalTimeline
        """
        super(Membership, self).save(*args, **kwargs)
        JournalTimeline.objects.create(journal=self.journal,
                                       collection=self.collection,
                                       publication_status=self.publication_status,
                                       publication_status_since=self.publication_status_since)

class JournalTimeline(models.Model):
    """
    Represents the status history of a journal.
    """
    journal = models.ForeignKey('Journal', related_name='statuses')
    collection = models.ForeignKey('Collection')

    publication_status = models.CharField(max_length=1,
        choices=[('c', 'current'), ('d', 'deceased')])
    publication_status_since = models.DateTimeField()

Me parece bom. No caso o StatusParty morre. Não encontrei referência para statuses na linha 12.

Eu até tinha pensado nisso na hora que escrevi no papel, mas não soube explicar direito.

Eu acho que teremos que começar o model-overhaul do zero :-/ mas tudo bem.

faz parte =]