Question

Imagine, I have News models with many text fields

class News(models.Model):

    title = models.CharField(max_length=255)
    subtitle = models.CharField(max_length=255, blank=True)
    lead = models.TextField(max_length=4096)
    content = models.TextField()
    ...
    last_visited = models.DateTimeField()

Every time my News object outputs, I update last_visited field:

news.last_visited = datetime.datetime.now()
news.save()

This code makes Django override all model fields:

UPDATE news SET title='...', subtitle='...', last_visited = '...' WHERE id = '...';

Instead of just one:

UPDATE news SET last_visited = '...' WHERE id = '...';

I worried how bad it is and is it worth of thinking about.

Django documentation offers queryset update but it looks not very elegant:

def upd(obj, **kwargs):
    obj.__class__._default_manager.filter(pk=obj.pk).update(**kwargs)

upd(news, last_visited=datetime.datetime.now())

I use mysql backend.

Answer 1

Using update but with a cleaner approach:

class News(models.Model):

    def update_visited(self):
        News.objects.filter(pk=self.pk).update(
                        last_visited=datetime.datetime.now())