Combining unrelated Models in Formset and saving results - django

Question

These are the models related to my problem:
Models.py
class SequenceDiagram(models.Model):
name = models.TextField(blank=True)
attributeMappingName = models.TextField(blank=True)
class AttributeFilter(models.Model):
seqDiagram = models.ForeignKey(SequenceDiagram)
attributeName = models.TextField(blank=True)
protocol = models.TextField()
isDisplayed = models.BooleanField(default=False)
class AttributeMapping(models.Model):
mappingName = models.TextField()
protocol = models.TextField(blank=True)
nativeName = models.TextField(blank=True)
customName = models.TextField(blank=True
Filters are specific to each SequenceDiagram but mappings are generic and applicable to different Diagrams.
I want a Formset with all AttributeFilters and AttributeMappings linked with the SequenceDiagram.
These are to be displayed in a table where isDisplayed and customName can be edited and then saved to the database.
How can I combine them to a Formset and then save the users changes?
Can a many-to-many relationship help solve my problem? If so, in which end should it be defined?
Please tell me if anything needs to be clarified.
edit
The resulting table should look like this:
Protocol|Native|Custom|Display
prot1 | Nat1 | Cus1 | Chkbx1
prot2 | Nat2 | Cus2 | Chkbx2
.......
So that matching customNames and isDisplayed are aligned.
I have tried using objects.extra() but I can't seem to save the changes to the 'other' model, I also don't know how to get the queryset to a Formfield and back.
AttributeFilter.objects.extra(
select={"protocol":"protocol", "sd":"sdAttributeName"},
where=["customName=nativeName"],
tables=["project_attributemapping"])

Answer 1

You can display both forms in the template and the process the forms separately in the view.
Here, we will be using ModelForms. We will create ModelForm for each model and then save all the models in a single view.
forms.py
from django import forms
from my_app.models import SequenceDiagram, AttributeFilter, AttributeMapping
class SequenceDiagramForm(forms.ModelForm):
class Meta:
model = SequenceDiagram
class AttributeFilterForm(forms.ModelForm):
class Meta:
model = AttributeFilter
exclude = (seqDiagram,)
class AttributeMappingForm(forms.ModelForm):
class Meta:
model = AttributeMapping
views.py
from django.views.generic import View
class MyView(View):
def post(self, request, *args, **kwargs):
sequence_diagram_form = SequenceDiagramForm(request.POST) # create form instance and populate with data
attribute_filter_form = AttributeFilterForm(request.POST) # create form instance and populate with data
attribute_mapping_form = AttributeMappingForm(request.POST) # create form instance and populate with data
sequence_diagram_form_valid = sequence_diagram_form.is_valid() # check if 'SequenceDiagramForm' is valid
attribute_filter_form_valid = attribute_filter_form.is_valid() # check if 'AttributeFilterForm' is valid
attribute_mapping_form_valid = attribute_mapping_form.is_valid() # check if 'AttributeMappingForm' is valid
# Check if all the forms are valid
if sequence_diagram_form_valid and attribute_filter_form_valid and attribute_mapping_form_valid:
sequence_diagram_obj = sequence_diagram_form.save() # save the SequenceDiagram object
attribute_filter_obj = attribute_filter_form.save(commit=False) # not save but get the instance
attribute_mapping_obj = attribute_mapping_form.save() # save the AttributeMapping object
attribute_filter_obj.seqDiagram = sequence_diagram_obj # set the `seqDiagram` to `sequence_diagram_obj`
attribute_filter_obj.save() # Now save the AttributeFilter object
...
# redirect to success page on all all forms being valid
...
# render the page again with errors if any of the form is invalid
In our view, we check if all the forms are valid and then only save all the 3 objects into db. If any of the form is invalid, then we don't save any of them.
For the case when any of the form is invalid, you can add the code to render the page again with the form errors.