Re: Don't understand ModelForm

[dan_mpi_cbg]

thank you, Shawn, for posting your working and tested example.  It
answered my questions (basically the same as the original post on this
thread) and got my head clear.

I agree in general with the point that the Django docs are not really
complete on this issue; I'd like it if the Forms/ModelForms would
throw out a complete CRUD example and explain each bit of it.

- dan




On Jul 21, 11:23 pm, Shawn Milochik  wrote:
> To expand on  what Dan said with a full (tested and working) example:
>
> In urls.py:
>
>      (r'^partner/$', 'partner_page'),
>      (r'^partner/(?P\d+)/$', 'partner_page'),
>
> In the form tag of your template:
>      
>
> The view:
>
> @login_required
> def partner_page(request, partner_id = None):
>
>      if partner_id:
>          #existing partner
>          partner_instance = get_object_or_404(partner, pk = partner_id)
>      else:
>          #new partner
>          partner_form = partnerForm()
>          partner_instance = None
>
>      if request.POST:
>          post_data = request.POST.copy()
>          partner_form = partnerForm(post_data, instance =  
> partner_instance)
>
>          if partner_form.is_valid():
>              the_partner = partner_form.save()
>              partner_id = the_partner.id
>
>      template_file = 'partner.html'
>
>      context = {
>          'partner_form': partner_form,
>          'partner_id': partner_id,
>      }
>
>      return render_to_response(template_file, context,  
> RequestContext(request))

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Re: Don't understand ModelForm

[ristretto.rb]

What I'm doing now is

#  TEMPLATE
{% if modelform.instance.id %}
  
{% endif %}

#  The POST part of the view method

pk = request.POST.get('pk',None)
if pk:
  model = models.House.objects.get(pk=pk)
  modelform = forms.MyModelForm(request.POST, instance=house)
else:
  modelform = forms.MyModelForm(request.POST)

Anyone else use this approach?

gene

On Aug 15, 12:07 pm, "ristretto.rb"  wrote:
> This is an excellent thread.  I came here with the same questions as
> Marc.  My revelation seems to be that forms are for data, and saving
> is control.  And these two have separate concerns/goals.  Such that
> fields shouldn't be in forms for the sole reason to make control of
> the form function properly.
>
> So you can put the id in you forms with a hidden, or in the action=""
> attribute, or using some sort of JavaScript, or whatever.  So, I
> understand that the key should be controlled outside the scope of the
> Django form support.
>
> But, I wonder if something like {{ form_set.management_form }} for
> formsets could be used here.  Perhaps something like
> {{form.indentifier_key}} on a template in the form could by default
> write out a hidden field of the pk of the instance.  It would just be
> shorthand for putting the instance in the context, and typing  type="hidden" name="pk" value="{{instance.id}}"/>
>
> But, it could make your view work like this, so you don't have to
> query up the model instance yourself.
>
>   f = your_modelform(request.POST)
>   f.instance #  would be the read from the DB and set for you.
>
> Gene
>
> On Jul 22, 9:23 am, Shawn Milochik  wrote:
>
> > To expand on  what Dan said with a full (tested and working) example:
>
> > In urls.py:
>
> >      (r'^partner/$', 'partner_page'),
> >      (r'^partner/(?P\d+)/$', 'partner_page'),
>
> > In the form tag of your template:
> >      
>
> > The view:
>
> > @login_required
> > def partner_page(request, partner_id = None):
>
> >      if partner_id:
> >          #existing partner
> >          partner_instance = get_object_or_404(partner, pk = partner_id)
> >      else:
> >          #new partner
> >          partner_form = partnerForm()
> >          partner_instance = None
>
> >      if request.POST:
> >          post_data = request.POST.copy()
> >          partner_form = partnerForm(post_data, instance =  
> > partner_instance)
>
> >          if partner_form.is_valid():
> >              the_partner = partner_form.save()
> >              partner_id = the_partner.id
>
> >      template_file = 'partner.html'
>
> >      context = {
> >          'partner_form': partner_form,
> >          'partner_id': partner_id,
> >      }
>
> >      return render_to_response(template_file, context,  
> > RequestContext(request))
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Re: Don't understand ModelForm

[ristretto.rb]

This is an excellent thread.  I came here with the same questions as
Marc.  My revelation seems to be that forms are for data, and saving
is control.  And these two have separate concerns/goals.  Such that
fields shouldn't be in forms for the sole reason to make control of
the form function properly.

So you can put the id in you forms with a hidden, or in the action=""
attribute, or using some sort of JavaScript, or whatever.  So, I
understand that the key should be controlled outside the scope of the
Django form support.

But, I wonder if something like {{ form_set.management_form }} for
formsets could be used here.  Perhaps something like
{{form.indentifier_key}} on a template in the form could by default
write out a hidden field of the pk of the instance.  It would just be
shorthand for putting the instance in the context, and typing 

But, it could make your view work like this, so you don't have to
query up the model instance yourself.

  f = your_modelform(request.POST)
  f.instance #  would be the read from the DB and set for you.

Gene


On Jul 22, 9:23 am, Shawn Milochik  wrote:
> To expand on  what Dan said with a full (tested and working) example:
>
> In urls.py:
>
>      (r'^partner/$', 'partner_page'),
>      (r'^partner/(?P\d+)/$', 'partner_page'),
>
> In the form tag of your template:
>      
>
> The view:
>
> @login_required
> def partner_page(request, partner_id = None):
>
>      if partner_id:
>          #existing partner
>          partner_instance = get_object_or_404(partner, pk = partner_id)
>      else:
>          #new partner
>          partner_form = partnerForm()
>          partner_instance = None
>
>      if request.POST:
>          post_data = request.POST.copy()
>          partner_form = partnerForm(post_data, instance =  
> partner_instance)
>
>          if partner_form.is_valid():
>              the_partner = partner_form.save()
>              partner_id = the_partner.id
>
>      template_file = 'partner.html'
>
>      context = {
>          'partner_form': partner_form,
>          'partner_id': partner_id,
>      }
>
>      return render_to_response(template_file, context,  
> RequestContext(request))
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Re: Don't understand ModelForm

[Shawn Milochik]

To expand on  what Dan said with a full (tested and working) example:

In urls.py:


 (r'^partner/$', 'partner_page'),
 (r'^partner/(?P\d+)/$', 'partner_page'),


In the form tag of your template:
 


The view:

@login_required
def partner_page(request, partner_id = None):

 if partner_id:
 #existing partner
 partner_instance = get_object_or_404(partner, pk = partner_id)
 else:
 #new partner
 partner_form = partnerForm()
 partner_instance = None

 if request.POST:
 post_data = request.POST.copy()
 partner_form = partnerForm(post_data, instance =  
partner_instance)

 if partner_form.is_valid():
 the_partner = partner_form.save()
 partner_id = the_partner.id

 template_file = 'partner.html'

 context = {
 'partner_form': partner_form,
 'partner_id': partner_id,
 }

 return render_to_response(template_file, context,  
RequestContext(request))







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Re: Don't understand ModelForm

[Dan Harris]

Oh I gotcha now.

Django model forms by default do not represent auto fields (ID's)
because it wouldn't make much sense for a user to be able to edit the
PK in a form. Having said that, I do understand why you need to be
able to see the PK.

I shown in my example, I personally prefer to represent the PK in the
url so something like

http://localhost/Partner/Edit/3 would be sent to the view:

def edit(request, id):

If you do not like doing it that way, you just have to pass the ID of
the partner object into your template. SInce you are saving your
partner object in session you can get access to it right away in the
template. Just alter your template a bit:


  
   
 {{ form.as_Table}}
   
   
   

Now you ahve Id available in your post data, so you can do your check.

if request.POST.get("partner_id"):
continue processing
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Re: Don't understand ModelForm

[mettwoch]

Of course! The mistake is that I didn't have the ID in the URL, but I
took the partner to be edited somewhere from the session. I'll change
the code and it should work as expected.

Thanks again for your patience

Marc

On Jul 21, 10:57 pm, Daniel Roseman  wrote:
> On Jul 21, 9:34 pm, mettwoch  wrote:
>
>
>
> > I'd like this to work:
>
> > class PartnerForm(forms.ModelForm):
> >     class Meta:
> >         model  = Partner  # I expect that all fields are included in
> > the form (the 'id' field as well)
>
> > def partner_new(request):
> >     form = PartnerForm()
> >     return render_to_response('pos.html', {'form': form},
> > RequestContext(request))
>
> > def partner_edit(request):
> >     form = PartnerForm(instance = request.session['partner'])
> >     return render_to_response('pos.html', {'form': form},
> > RequestContext(request))
>
> > def partner_save(request):
> >     if request.POST.get('id', None):
> >         form = PartnerForm(request.POST, instance = get_object_or_404
> > (Partner, pk = request.POST['id']))
> >     else:
> >         form = PartnerForm(request.POST)
> >     if form.is_valid():
> >         form.save()
> >         return render_to_response('pos.html', {}, RequestContext
> > (request))
> >     else:
> >         return render_to_response('pos.html', {'form': form},
> > RequestContext(request))
>
> > here's an excerpt of the pos.html:
>
> >             {% if form %}
> >                 
> >                     
> >                         {{ form.as_table }}
> >                     
> >                     
> >                 
> >             ...
>
> > as I said: maybe I'm on the wrong track with ModelForm ...
>
> Well, yes. What you've posted doesn't make any sense at all. You want
> to get the id from the form, so that you can get the instance from the
> database to pass to the form so it can get the id! This is obviously
> circular. At some point, you've got to tell the form what the id
> actually is, and that means passing it in to the page where you first
> render the form. If you don't have an id, you pass a blank instance,
> and a new row will be made in the database. If you do have one, pass
> the instance with that id, and the existing row will be edited.
>
> Various people have posted more or less complex code to do this, but
> the simplest is like this:
>
> def my_form_view(request, partner_id=None):
>     if partner_id:
>         partner = Partner.objects.get(id=partner_id)
>     else:
>         partner = Partner()
>
>     if request.POST:
>         form = PartnerForm(request.POST, instance=partner)
>         if form.is_valid():
>             form.save()
>             return HttpResponseRedirect('/')
>     else:
>         form = PartnerForm(instance=partner)
>
>     return render_to_response('pos.html', {'form': form},
> RequestContext(request))
>
> One final thing - make your form action="." so it posts back to the
> same URL, ie the one with the partner_id.
>
> That's all there is to it - nothing complicated at all.
> --
> DR.
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Re: Don't understand ModelForm

[Daniel Roseman]

On Jul 21, 9:34 pm, mettwoch  wrote:
> I'd like this to work:
>
> class PartnerForm(forms.ModelForm):
>     class Meta:
>         model  = Partner  # I expect that all fields are included in
> the form (the 'id' field as well)
>
> def partner_new(request):
>     form = PartnerForm()
>     return render_to_response('pos.html', {'form': form},
> RequestContext(request))
>
> def partner_edit(request):
>     form = PartnerForm(instance = request.session['partner'])
>     return render_to_response('pos.html', {'form': form},
> RequestContext(request))
>
> def partner_save(request):
>     if request.POST.get('id', None):
>         form = PartnerForm(request.POST, instance = get_object_or_404
> (Partner, pk = request.POST['id']))
>     else:
>         form = PartnerForm(request.POST)
>     if form.is_valid():
>         form.save()
>         return render_to_response('pos.html', {}, RequestContext
> (request))
>     else:
>         return render_to_response('pos.html', {'form': form},
> RequestContext(request))
>
> here's an excerpt of the pos.html:
>
>             {% if form %}
>                 
>                     
>                         {{ form.as_table }}
>                     
>                     
>                 
>             ...
>
> as I said: maybe I'm on the wrong track with ModelForm ...

Well, yes. What you've posted doesn't make any sense at all. You want
to get the id from the form, so that you can get the instance from the
database to pass to the form so it can get the id! This is obviously
circular. At some point, you've got to tell the form what the id
actually is, and that means passing it in to the page where you first
render the form. If you don't have an id, you pass a blank instance,
and a new row will be made in the database. If you do have one, pass
the instance with that id, and the existing row will be edited.

Various people have posted more or less complex code to do this, but
the simplest is like this:

def my_form_view(request, partner_id=None):
if partner_id:
partner = Partner.objects.get(id=partner_id)
else:
partner = Partner()

if request.POST:
form = PartnerForm(request.POST, instance=partner)
if form.is_valid():
form.save()
return HttpResponseRedirect('/')
else:
form = PartnerForm(instance=partner)

return render_to_response('pos.html', {'form': form},
RequestContext(request))

One final thing - make your form action="." so it posts back to the
same URL, ie the one with the partner_id.

That's all there is to it - nothing complicated at all.
--
DR.
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Re: Don't understand ModelForm

[mettwoch]

I'd like this to work:

class PartnerForm(forms.ModelForm):
class Meta:
model  = Partner  # I expect that all fields are included in
the form (the 'id' field as well)

def partner_new(request):
form = PartnerForm()
return render_to_response('pos.html', {'form': form},
RequestContext(request))

def partner_edit(request):
form = PartnerForm(instance = request.session['partner'])
return render_to_response('pos.html', {'form': form},
RequestContext(request))

def partner_save(request):
if request.POST.get('id', None):
form = PartnerForm(request.POST, instance = get_object_or_404
(Partner, pk = request.POST['id']))
else:
form = PartnerForm(request.POST)
if form.is_valid():
form.save()
return render_to_response('pos.html', {}, RequestContext
(request))
else:
return render_to_response('pos.html', {'form': form},
RequestContext(request))

here's an excerpt of the pos.html:

{% if form %}


{{ form.as_table }}



...

as I said: maybe I'm on the wrong track with ModelForm ...



On Jul 21, 10:22 pm, Dan Harris  wrote:
> What do you mean by having the ID "in" the form? I don't quite
> understand what you are trying to do.
>
> On Jul 21, 4:15 pm, mettwoch  wrote:
>
> > Ok, I come back to what I wrote before. If the partner already exists
> > it has an id (primary-key or whatever). If it doesn't exist it has no
> > id. I'd just like to have the id in the form. Is it a bug, is
> > something missing here or am I completely on the wrong track. That's
> > basic database form handling. Well I could fallback to using Form
> > instead of ModelForm and maybe I'll manage to get that id in the form
> > as a hidden field or whatever, but I wonder how such basic things seem
> > impossible with the ModelForm.
>
> > Thanks for Your patience
>
> > Marc
>
> > On Jul 21, 9:55 pm, Shawn Milochik  wrote:
>
> > > On Jul 21, 2009, at 3:39 PM, mettwoch wrote:
>
> > > > Sorry to insist, but that's what I don't understand here. How can I
> > > > know that the partner that is 'posted' is new or not? I really become
> > > > crazy here. I can't believe after all the good things I've discovered
> > > > in Django that this can be so hard.
>
> > > Okay, thanks for clarifying.
>
> > > Well, you can have the partner identified in the URL by a slug or  
> > > something, for one. That's probably the easiest way. You do need to  
> > > track it somehow, starting when you pull the instance from the  
> > > database to populate the ModelForm. Otherwise, how can you know that  
> > > it's someone new versus someone with the same details?
>
> > > The way I'm doing it is by having separate views and urls for editing  
> > > and creating a new entry. But in any case you have to write something  
> > > somewhere when you are pulling an existing record.
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Re: Don't understand ModelForm

[Shawn Milochik]

On Jul 21, 2009, at 4:22 PM, Dan Harris wrote:

>
> What do you mean by having the ID "in" the form? I don't quite
> understand what you are trying to do.
>
> On Jul 21, 4:15 pm, mettwoch  wrote:
>> Ok, I come back to what I wrote before. If the partner already exists
>> it has an id (primary-key or whatever). If it doesn't exist it has no
>> id. I'd just like to have the id in the form. Is it a bug, is
>> something missing here or am I completely on the wrong track. That's
>> basic database form handling. Well I could fallback to using Form
>> instead of ModelForm and maybe I'll manage to get that id in the form
>> as a hidden field or whatever, but I wonder how such basic things  
>> seem
>> impossible with the ModelForm.
>>
>> Thanks for Your patience
>>
>> Marc
>>


What he's referring to is the fact that, if you're using a ModelForm,  
the model's ID is not available in the template.

And my answer to the question is that I use the ID (or a slug) in both  
the URL and in the form's "action" argument, so that
when it's submitted, you have the info you need in the request.

Just as a quick example:

(r'^patient/(?P[-\w]+)/$', 'view'),

This will pass the variable "slug" to the view, and the slug is used  
to identify the patient. If you don't use
slugs, the ID works just as well (although it makes for less friendly- 
looking URLs).



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Re: Don't understand ModelForm

[Dan Harris]

What do you mean by having the ID "in" the form? I don't quite
understand what you are trying to do.

On Jul 21, 4:15 pm, mettwoch  wrote:
> Ok, I come back to what I wrote before. If the partner already exists
> it has an id (primary-key or whatever). If it doesn't exist it has no
> id. I'd just like to have the id in the form. Is it a bug, is
> something missing here or am I completely on the wrong track. That's
> basic database form handling. Well I could fallback to using Form
> instead of ModelForm and maybe I'll manage to get that id in the form
> as a hidden field or whatever, but I wonder how such basic things seem
> impossible with the ModelForm.
>
> Thanks for Your patience
>
> Marc
>
> On Jul 21, 9:55 pm, Shawn Milochik  wrote:
>
>
>
> > On Jul 21, 2009, at 3:39 PM, mettwoch wrote:
>
> > > Sorry to insist, but that's what I don't understand here. How can I
> > > know that the partner that is 'posted' is new or not? I really become
> > > crazy here. I can't believe after all the good things I've discovered
> > > in Django that this can be so hard.
>
> > Okay, thanks for clarifying.
>
> > Well, you can have the partner identified in the URL by a slug or  
> > something, for one. That's probably the easiest way. You do need to  
> > track it somehow, starting when you pull the instance from the  
> > database to populate the ModelForm. Otherwise, how can you know that  
> > it's someone new versus someone with the same details?
>
> > The way I'm doing it is by having separate views and urls for editing  
> > and creating a new entry. But in any case you have to write something  
> > somewhere when you are pulling an existing record.
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Re: Don't understand ModelForm

[mettwoch]

Ok, I come back to what I wrote before. If the partner already exists
it has an id (primary-key or whatever). If it doesn't exist it has no
id. I'd just like to have the id in the form. Is it a bug, is
something missing here or am I completely on the wrong track. That's
basic database form handling. Well I could fallback to using Form
instead of ModelForm and maybe I'll manage to get that id in the form
as a hidden field or whatever, but I wonder how such basic things seem
impossible with the ModelForm.

Thanks for Your patience

Marc

On Jul 21, 9:55 pm, Shawn Milochik  wrote:
> On Jul 21, 2009, at 3:39 PM, mettwoch wrote:
>
>
>
> > Sorry to insist, but that's what I don't understand here. How can I
> > know that the partner that is 'posted' is new or not? I really become
> > crazy here. I can't believe after all the good things I've discovered
> > in Django that this can be so hard.
>
> Okay, thanks for clarifying.
>
> Well, you can have the partner identified in the URL by a slug or  
> something, for one. That's probably the easiest way. You do need to  
> track it somehow, starting when you pull the instance from the  
> database to populate the ModelForm. Otherwise, how can you know that  
> it's someone new versus someone with the same details?
>
> The way I'm doing it is by having separate views and urls for editing  
> and creating a new entry. But in any case you have to write something  
> somewhere when you are pulling an existing record.
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Re: Don't understand ModelForm

[Dan Harris]

This may not be helpful but here is how I usually go about processing
model forms:

class Partner(models.Model):
# this is your model, DB fields go in here

# This is your model form
class PartnerForm(forms.ModelForm):
   class Meta:
  model = Partner

# This is the view that displays a new partner form or processes the
form
def new(request):
form = PartnerForm()
if request.method=="POST":
# if there is a post, they are sending in the form so re-
create the form from the post data
form = PartnerForm(request.POST)
if form.is_valid():
 p = form.save()   # save the form and store the resulting
Partner object in p
 return HttpResponseRedirect("/success")  # always
redirect after processing a form to revent refresh spam

# if we got to this point it means it wasn't a POST and we didn't
process a form, or the form was invalid
   # either way, render whatever we had with errors and what not
return render_to_response('new_partner_template.html', {'form':
form})

# This is a view to edit and existing parter
def edit(request, id):   # ID is the partners identifying number such
as primary key, SSN, whatever you want
p = get_object_or_404(Partner, pk=id)   # this will throw a 404 if
they requested an invalid partner
form = PartnerForm(instance=p)   # create a form pre-populated
with the partner data we just loaded
if request.method=='POST':
# now process the submitted form
form = PartnerForm(request.POST, instance=p)   # this creats a
form using the database data AND the post data
if form.is_valid():
 p = form.save()
 return HttpResponseRedirect('/success')

# if we got down here, they didn't submit the form, or they did
and there were errors, so render it back
   return render_to_response('my_template.html', {'form': form})

This is how I do it, If you have any further questions I can try to
help. Please note this code was off the top of my head, so it may not
compile "out of the box"

Dan
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Re: Don't understand ModelForm

[Shawn Milochik]

On Jul 21, 2009, at 3:39 PM, mettwoch wrote:

>
> Sorry to insist, but that's what I don't understand here. How can I
> know that the partner that is 'posted' is new or not? I really become
> crazy here. I can't believe after all the good things I've discovered
> in Django that this can be so hard.
>

Okay, thanks for clarifying.

Well, you can have the partner identified in the URL by a slug or  
something, for one. That's probably the easiest way. You do need to  
track it somehow, starting when you pull the instance from the  
database to populate the ModelForm. Otherwise, how can you know that  
it's someone new versus someone with the same details?

The way I'm doing it is by having separate views and urls for editing  
and creating a new entry. But in any case you have to write something  
somewhere when you are pulling an existing record. 

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Re: Don't understand ModelForm

[mettwoch]

Sorry to insist, but that's what I don't understand here. How can I
know that the partner that is 'posted' is new or not? I really become
crazy here. I can't believe after all the good things I've discovered
in Django that this can be so hard.

Thanks for your time
>
> You are right, I made a mistake there. I typed it off of the top of my  
> head, instead of copying and pasting from working code.
>
> All you have to do is what I did above in the create -- have an if  
> statement. If the partner already exists, you have to get
> that object (using the Partner.objects.get(your_criteria_here) and  
> pass it using the 'instance' keyword.
>
> Something like:
>
> #if it's an existing partner:
> partner_form = PartnerForm(instance = partner_instance)
>
> #else:
> partner_form = PartnerForm(request.POST)
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Re: Don't understand ModelForm

[Shawn Milochik]

>
> This always creates a new partner! In fact, in the ModelForm
> documentation is written that the save() method creates a new instance
> unless an existing instance is passed to the ModelForm constructor. So
> one has to differentiate if the POST comes from an initially empty
> form or from a bound form! How can this be done? I believe that it
> could be easily achieved if the primary-key were always included as a
> hidden field. If it's empty, then 'create' otherwise 'get' & 'update'.
>
>>
>> DELETE:
>> #if you have a partner object named partner_instance
>> partner_instance.delete()
>>
>> READ:
>> What do you mean?
>> Partner.objects.get(pk = 12) #or whatever


You are right, I made a mistake there. I typed it off of the top of my  
head, instead of copying and pasting from working code.

All you have to do is what I did above in the create -- have an if  
statement. If the partner already exists, you have to get
that object (using the Partner.objects.get(your_criteria_here) and  
pass it using the 'instance' keyword.

Something like:

#if it's an existing partner:
partner_form = PartnerForm(instance = partner_instance)

#else:
partner_form = PartnerForm(request.POST)
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Re: Don't understand ModelForm

[mettwoch]

Hi again,

That's exactly what I did and the point is that it doesn't work! See
my comments below ...

On Jul 21, 8:00 pm, Shawn Milochik  wrote:
> On Jul 21, 2009, at 12:49 PM, mettwoch wrote:
>
>
>
> > Sorry my old brain doesn't get it. Is there somewhere a complete CRUD
> > example using ModelForm?
>
> > Thanks
> > Marc
>
> CRUD:
>
> If your modelform is called PartnerForm, then.
>
> CREATE and UPDATE:
>
>         #on initial page load (no POST)
>
>         #if you have a partner object already (named partner_instance):
>         partner_form = PartnerForm(instance = partner_instance)
>         #otherwise:
>         partner_form = PartnerForm()
>
>         #in the POST portion of your view
>         partner_form = PartnerForm(request.POST)
>         if partner_form.is_valid():
>                 partner_form.save()

This always creates a new partner! In fact, in the ModelForm
documentation is written that the save() method creates a new instance
unless an existing instance is passed to the ModelForm constructor. So
one has to differentiate if the POST comes from an initially empty
form or from a bound form! How can this be done? I believe that it
could be easily achieved if the primary-key were always included as a
hidden field. If it's empty, then 'create' otherwise 'get' & 'update'.

>
> DELETE:
>         #if you have a partner object named partner_instance
>         partner_instance.delete()
>
> READ:
>         What do you mean?
>         Partner.objects.get(pk = 12) #or whatever

In my specific case the partner is stored in the session and it can be
updated. When a new partner is created it is stored in the session.
There's always an 'actif' partner.

>
>         #or, from the modelform instance, assuming
>         #something like partner_form = PartnerForm(instance = 
> partner_instance)
>         #has happened:
>         if partner_form.is_valid():
>                 partner_name = partner_form.cleaned_data['name']
>
> I hope this helps. If not, please be more specific.
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Re: Don't understand ModelForm

[Shawn Milochik]

On Jul 21, 2009, at 12:49 PM, mettwoch wrote:

>
> Sorry my old brain doesn't get it. Is there somewhere a complete CRUD
> example using ModelForm?
>
> Thanks
> Marc

CRUD:

If your modelform is called PartnerForm, then.

CREATE and UPDATE:

#on initial page load (no POST)

#if you have a partner object already (named partner_instance):
partner_form = PartnerForm(instance = partner_instance)
#otherwise:
partner_form = PartnerForm()

#in the POST portion of your view
partner_form = PartnerForm(request.POST)
if partner_form.is_valid():
partner_form.save()

DELETE:
#if you have a partner object named partner_instance
partner_instance.delete()

READ:
What do you mean?
Partner.objects.get(pk = 12) #or whatever

#or, from the modelform instance, assuming
#something like partner_form = PartnerForm(instance = partner_instance)
#has happened:
if partner_form.is_valid():
partner_name = partner_form.cleaned_data['name']

I hope this helps. If not, please be more specific.



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Re: Don't understand ModelForm

[mettwoch]

Sorry my old brain doesn't get it. Is there somewhere a complete CRUD
example using ModelForm?

Thanks
Marc

On Jul 21, 6:04 pm, Shawn Milochik  wrote:
> On Jul 21, 2009, at 12:00 PM, mettwoch wrote:
>
>
>
>
>
> > Hi,
>
> > I'd like to implement a simple "create" & "update" form for my
> > "Partner" model using ModelForm. How can I make the difference in a
> > view "save" function whether the POST comes from a "creation" or an
> > "update" form? Unfortunately the primary-key seems never to be
> > included by default in the form fields! This would have made it easy.
>
> > Got 3 view functions:
> > new(request):
> >   
>
> > edit(request, partner):
> >   
>
> > save(request):
> >    >         update partner
> >    else:
> >        create partner
>
> > Many thanks for any hint
> > Marc
>
> You don't need the save version. Your edit form will save the object  
> instance whether it's new or not, with the .save() method. This is one  
> of the nice things about Django models -- it simplifies things. If you  
> need to do something differently depending on whether the object is  
> being saved for the first time, you do it by overriding the save()  
> method in the model itself.
>
> Shawn
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Re: Don't understand ModelForm

[Shawn Milochik]

On Jul 21, 2009, at 12:00 PM, mettwoch wrote:

>
> Hi,
>
> I'd like to implement a simple "create" & "update" form for my
> "Partner" model using ModelForm. How can I make the difference in a
> view "save" function whether the POST comes from a "creation" or an
> "update" form? Unfortunately the primary-key seems never to be
> included by default in the form fields! This would have made it easy.
>
> Got 3 view functions:
> new(request):
>   
>
> edit(request, partner):
>   
>
> save(request):
>update partner
>else:
>create partner
>
> Many thanks for any hint
> Marc
>
> >

You don't need the save version. Your edit form will save the object  
instance whether it's new or not, with the .save() method. This is one  
of the nice things about Django models -- it simplifies things. If you  
need to do something differently depending on whether the object is  
being saved for the first time, you do it by overriding the save()  
method in the model itself.

Shawn

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Don't understand ModelForm

[mettwoch]

Hi,

I'd like to implement a simple "create" & "update" form for my
"Partner" model using ModelForm. How can I make the difference in a
view "save" function whether the POST comes from a "creation" or an
"update" form? Unfortunately the primary-key seems never to be
included by default in the form fields! This would have made it easy.

Got 3 view functions:
new(request):
   

edit(request, partner):
   

save(request):
   http://groups.google.com/group/django-users?hl=en
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