transaction.py

class Transaction(models.Model):
    owner = models.ForeignKey('auth.User')
    datetime = models.DateTimeField(auto_now_add=True)
    amount = models.PositiveIntegerField()
    approved = models.BooleanField(default=False)
    result = models.PositiveIntegerField(blank=True, null=True)
    error = models.TextField(blank=True, null=True)
    error_code = models.PositiveIntegerField(blank=True, null=True)

    def operation_result(self):
        if self.approved:
            return self.result
        else:
            return "{0} {1}".format(self.error_code, self.error)

    class Meta:
        ordering = ("-datetime", )

class TransactionHistory(models.Model):
    OPERATION_CHOICES = (
        (BUY, u'Покупка'),
        (CASH_PAYMENT_IN, u'Начисление на счет'),
        (CASH_PAYMENT_OUT, u'Вывод со счета'),
    )

    datetime = models.DateTimeField(verbose_name=u'Дата операции', auto_now=True)
    user = models.ForeignKey('auth.User', verbose_name=u'Пользователь')
    operation_amount = models.FloatField(verbose_name=u'Сумма операции')
    start_user_amount = models.FloatField(verbose_name=u'Сумма пользователя на начало опрации')
    finish_user_amount = models.FloatField(verbose_name=u'Сумма пользователя на конец опрации')
    operation = models.IntegerField(verbose_name=u'Операция',
                                    choices=OPERATION_CHOICES)
    content_type = models.ForeignKey(ContentType, blank=True, null=True)
    object_id = models.PositiveIntegerField(blank=True, null=True)
    operation_object = generic.GenericForeignKey('content_type', 'object_id')


    def __unicode__(self):
        return '%s %s' % (self.profile.__unicode__(), self.get_operation_display())

    class Meta:
        verbose_name = u'Дейcтвие'
        verbose_name_plural = u'История действий'
        ordering = ['-datetime']