Form 'POST' to a database

[JJ Zolper]

I honestly just have a general question.

If I have one database set in my settings file in settings.py and I try to execute a simple HTML Form using 'POST' how do I get that data into my PostgreSQL database?

In my view do I have to interface with my model and thus the model takes care of the rest?

https://docs.djangoproject.com/en/1.4/topics/forms/modelforms/

This link seems to be down the right road I think?

I'm sorry if this question does not make a lot of sense but I really am trying to find some direction as to how once I have a view, model, urlconf, and settings file with a database tied to it (i checked using the import django.db connection/cursor test) how do I get the request.POST data sent to my database?

Thanks,

JJ

[Lee Hinde]

I recommend the tutorial. It walks you through the process, soup to nuts.

https://docs.djangoproject.com/en/dev/intro/tutorial01/

[JJ Zolper]

I guess on Part 4 is what I need...

So hmmm.

def vote(request, poll_id):
    p = get_object_or_404(Poll, pk=poll_id)
    try:
        selected_choice = p.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        # Redisplay the poll voting form.
        return render_to_response('polls/detail.html', {
            'poll': p,
            'error_message': "You didn't select a choice.",
        }, context_instance=RequestContext(request))
    else:
        selected_choice.votes += 1
        selected_choice.save()
        # Always return an HttpResponseRedirect after successfully dealing
        # with POST data. This prevents data from being posted twice if a
        # user hits the Back button.
        return HttpResponseRedirect(reverse('polls.views.results', args=(p.id,)))

So originally:

        selected_choice = p.choice_set.get(pk=request.POST['choice'])

this requests the submitted choice from the POST data and 

The part that says:

        selected_choice.votes += 1
        selected_choice.save()

Actually saves the choice to the database?

Is it just two lines? requesting the data form request.POST and then that variable.save() to store it in the database?

JJ

[Andre Schemschat]

Hey,

yeah, it basicly is. Just a very, very basic example (And sorry if i could highlight this as code, i didnt find something in the format-menu :/ ).

Of course you should validate your input first. And if you just want to edit a Model within a form, you should check on the ModelForm-Class https://docs.djangoproject.com/en/dev/topics/forms/modelforms/

def vote(request, poll_id):

    try:

        obj = YourModel.objects.get(pk=poll_id)

        obj.attributea = request.POST['attributea']

        obj.attributeb = request.POST['attributeb']

        obj.save()

        return HttpResponse(validparamshere)

    except ObjectDoesNotExist:

        return HttpResponse(show_some_error)

[Jani Tiainen]

Django makes always (at least currently) full record update (iow: there is no dirty flag for fields).

Example given is "poor" in the sense that it uses directly POST data. I strongly would suggest leveraging modelforms when ever possible - it saves time and nerves. You get all the validation and other goodies for free.

On Wed, Jul 11, 2012 at 8:09 PM, Dennis Lee Bieber <wlf...@ix.netcom.com> wrote:

On Wed, 11 Jul 2012 08:36:39 -0700 (PDT), JJ Zolper
<codin...@gmail.com> declaimed the following in
gmane.comp.python.django.user:

> So originally:
>
>         selected_choice = p.choice_set.get(pk=request.POST['choice'])
>

        If I understand this (I've not run the tutorial, and only browsed
the now-outdated print books), this statement is using the value from
the "choice" field of the submitted form as the primary key to retrieve
a record (model instance) from the database.

pseudo-SQL
select * from choice_set where pk = "request.POST['choice']"

> this requests the submitted choice from the POST data and
>
> The part that says:
>
>         selected_choice.votes += 1
>         selected_choice.save()
>
> Actually saves the choice to the database?
>

        This then increments the votes field of the record (model instance)
retrieved from the database, and then saves the record back.

p-SQL
update choice_set set
        votes = votes + 1
where pk = selected_choice.pk

{I don't know if Django is smart enough to only update the changed
field, or if it updates the entire record}
--
        Wulfraed                 Dennis Lee Bieber         AF6VN
        wlf...@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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Jani Tiainen

- Well planned is half done, and a half done has been sufficient before...

[JJ Zolper]

I was able to make it work!

from django.core.context_processors import csrf

from django.template import RequestContext

from django.http import HttpResponseRedirect

from django.http import HttpResponse

from django.shortcuts import render_to_response

from MadTrak.manageabout.models import AboutMadtrak, AboutMadtrakForm

def about(request):

AboutMadtrakInstance = AboutMadtrak()

result = AboutMadtrakForm(request.POST, instance=AboutMadtrakInstance)

result.save()

        return HttpResponse('It worked?!? Of course it did. I knew that.')

def about_form(request):

    return render_to_response('about_form.html', context_instance = RequestContext(request))

I ended up looking at ModelForms and trying that since I was having issues.

So does this method handle all validation and security issues for me?

Or do I still need a "result.is_valid()" among other things?

[JJ Zolper]

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[JJ Zolper]

On Wednesday, July 11, 2012 1:09:32 PM UTC-4, Dennis Lee Bieber wrote:

On Wed, 11 Jul 2012 08:36:39 -0700 (PDT), JJ Zolper
<codin...@gmail.com> declaimed the following in
gmane.comp.python.django.user:

> So originally:
>
>         selected_choice = p.choice_set.get(pk=request.POST['choice'])
>

        If I understand this (I've not run the tutorial, and only browsed
the now-outdated print books), this statement is using the value from
the "choice" field of the submitted form as the primary key to retrieve
a record (model instance) from the database.

pseudo-SQL
select * from choice_set where pk = "request.POST['choice']"

> this requests the submitted choice from the POST data and
>
> The part that says:
>
>         selected_choice.votes += 1
>         selected_choice.save()
>
> Actually saves the choice to the database?
>

[Jani Tiainen]

You still need to call result.is_valid() since it actually runs actual validation rules.

Very basic form processing is usually done like this:

so in case of GET you return empty form. in case of invalid POST you return form with values and error messages.

After successful POST you do redirect-after-post to avoid problems with browser history back-button.

def form_view(request):

    if request.method == 'POST':

        form = MyForm(request.POST)

        if form.is_valid():

            form.save()

            return HttpResponseRedirect("/some/result/form")

    else:

        form = MyForm()    

    return HttpResponse("form/form.html", { 'form': form })

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[JJ Zolper]

Thank you so much for the clarification!

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