How to save a model in ModelForm with two ForeignKey fields in Django

Question

There is a model Listaflor linked to Estados with another model named Flora2Estado, i made a form with ModelMultipleChoiceField. It saves successfully into Listaflor but nothing into the Flora2Estado, what can i do about this?

forms.py

class FloForm(forms.ModelForm):
    familia = forms.ModelChoiceField(queryset=Familia.objects.all().order_by('familia_nome').filter(aprovado=1))
    Especie = forms.CharField(label="Nome da espécie*")
    estados = forms.ModelMultipleChoiceField(queryset=EstadosM.objects.all().order_by('nome_abbr'))
    class Meta:
        model = Listaflor
        ordering = ["estados",]
        fields = ['Especie','estados']

views.py

def CreateFlo(request):
    form = FloForm()
    if request.method == 'POST':
        form = FloForm(request.POST)
        if form.is_valid():
            Listaflor = form.save(commit=False)
            Flora2Estado = form.save(commit=False)
            Listaflor.save()
            Flora2Estado.save()
  
    return render(request,'accounts/enviar_flora.html')

models.py

class Flora2Estado(models.Model):
    estado = models.ForeignKey(EstadosM, models.CASCADE)
    especie = models.ForeignKey(Listaflor, models.CASCADE)
    flora2estado = models.AutoField(primary_key=True)
    class Meta:
        managed = False
        db_table = 'flora2estado'
        unique_together = (('estado', 'especie'),)

Any tips on helping me making a better post is welcome, have a good day!

View.py updated: returning Validation error!

def CreateFlo(request):    
    EstadosInlineFormSet  = inlineformset_factory(Listaflor, Flora2Estado, form=Flo2Form)
    Form = FloForm(request.POST)
    storeForm = FloForm(request.POST)
    if Form.is_valid():
        new_store = storeForm.save()
        florInlineFormSet = EstadosInlineFormSet(request.POST or None, request.FILES or None, instance=new_store)

        if florInlineFormSet.is_valid():
            florInlineFormSet.save()
    context = {'form': Form}
    return render(request,'accounts/enviar_flora.html', context)

models.py:

class Flora2Estado(models.Model):
    estado = models.ForeignKey(EstadosM, models.CASCADE)
    especie = models.ForeignKey(Listaflor, models.CASCADE)
    flora2estado = models.AutoField(primary_key=True)
    class Meta:
        managed = False
        db_table = 'flora2estado'
        unique_together = (('estado', 'especie'),)
class Listaflor(models.Model):
    especie_id = models.AutoField(primary_key=True)
    familia = models.ForeignKey(Familia, models.DO_NOTHING, db_column='familia_id', blank=True, null=True)
    Especie = models.CharField(db_column='especie', max_length=255, blank=True, null=True) 

I tried this:

def CreateFlo(request):
    form = FloForm()
    if request.method == 'POST':
        form = FloForm(request.POST)
        if form.is_valid():
            listafor = form.save()
            estados = form.cleaned_data.get('estados')
            for estado in estados:
                Flora2Estado.objects.create(especie=listafor, estado= estado)
    texto="..."
    context = {'floForm': form,'texto': texto}
    return render(request, 'accounts/enviar_flora.html', context)

got the error:

django.db.utils.IntegrityError: (1062, "Duplicate entry '18-3256' for key 'PRIMARY'")

Answer 1

It is because you have clearly mentioned Listaflor here:

class Meta:
    model = Listaflor

Eventhough if you've changed it to

class Meta:
    model = Flora2Estado

You can't save the ForeignKey fields in Flora2Estado like that.

Let's have a look at this on Saving Django ModelForm with a ForeignKey

Answer 2

You can specify two unique prefixes to differentiate between the forms:

form1 = FloForm(prefix='form-1')
form2 = FloForm(prefix='form-2')
if request.method == 'POST':
    form1 = FloForm(request.POST,prefix='form-1')
    form2 = FloForm(request.POST,prefix='form-2')
    if form.is_valid():
        Listaflor = form1.save(commit=False)
        Flora2Estado = form2.save(commit=False)
        Listaflor.save()
        Flora2Estado.save()

Answer 3

You can try to extract out the estados from form's cleaned_data, like this:

def CreateFlo(request):
    form = FloForm()
    if request.method == 'POST':
        form = FloForm(request.POST)
        if form.is_valid():
            listafor = form.save()
            estados = form.cleaned_data.get('estados')
            for estado in estados:
                Flora2Estado.objects.create(especie=listafor, estado= estado)
            # or you can use bulk_create: https://docs.djangoproject.com/en/3.0/ref/models/querysets/#bulk-create
  
    return render(request,'accounts/enviar_flora.html')

Update

It is really hard to tell for which model you are getting the error, but my assumption is Listaflor model. It is a possibility that you have a primary key field in which default value is “18-XXXX”. When you are creating Listaflor instance using the FloForm, you are not providing any primary key value, so it is taking the default value as primary key, hence throwing Integrity error. To solve this you can either use a dynamic function to generate the value of primary key or use UUIDField/AutoField to generate primary key automatically.