Hi Alex,
Thanks for your reply. Yes, I had found and experimented with both
has_changed() and changed_data(), but I found that they don't deal as
I'd like with my case where my form contains fields that are not in
the model. IE, using the Book example, if I have
model Book(models.Model):
name = models.CharField()
model Author(models.Model)
books = models.ManyToManyField(Book)
If I create a BookForm that is like this, that allows the user to put
in the authors:
class BookForm(forms.ModelForm)
authors = forms.CharField(widget=forms.Textarea, help_text="space
separated list of authors")
class Meta:
model=Book
I find that changed_data() always returns 'authors' and has_changed is
always True. I will take a look at the source a bit more.
Margie
On Feb 25, 4:59 pm, Alex Gaynor <alex.gay...@gmail.com> wrote:
> On Wed, Feb 25, 2009 at 7:55 PM, Margie <margierogin...@yahoo.com> wrote:
>
> > Say I create a form that reflects the current state of an object. The
> > user can edit that form, and when they click 'save', I get back the
> > new, possibly edited, values via the POST. In my POST code I do
> > something like this:
>
> > postDict = request.POST.copy()
> > bookForm = BookForm(postDict, instance=bookObj)
> > if bookForm.is_valid()
> > bookForm.save()
>
> > What do folks typically do to avoid saving the data if nothing has
> > been modified in the form? Is there any django functionality for
> > doing this, or do I just write the manual check that compares the
> > fields in the form to the fields in the existing object?
>
> > I'm not only concerned with the database access. In addition to
> > avoiding the save, I'd like to emit a message to the user that
> > reflects what they've done, or not done. IE, "book foo updated' or
> > "book foo unchanged".
>
> > Anyway, just curious if others have encountered this.
>
> > Margie
>
> > Form's have a method "has_changed" which says whether or not there is
>
> changed data, this should do just what you expect.
>
> Alex
>
> --
> "I disapprove of what you say, but I will defend to the death your right to
> say it." --Voltaire
> "The people's good is the highest law."--Cicero
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