fields.py 文件源码

def find_unique(self, model_instance, field, iterator, *args):
        # exclude the current model instance from the queryset used in finding
        # next valid hash
        queryset = self.get_queryset(model_instance.__class__, field)
        if model_instance.pk:
            queryset = queryset.exclude(pk=model_instance.pk)

        # form a kwarg dict used to impliment any unique_together contraints
        kwargs = {}
        for params in model_instance._meta.unique_together:
            if self.attname in params:
                for param in params:
                    kwargs[param] = getattr(model_instance, param, None)

        new = six.next(iterator)
        kwargs[self.attname] = new
        while not new or queryset.filter(**kwargs):
            new = six.next(iterator)
            kwargs[self.attname] = new
        setattr(model_instance, self.attname, new)
        return new