Django: Get model field data from a model field data

Question

I have something like this in views.py.

    if form.is_valid():

        ref_user = User.objects.get(
        username=form.cleaned_data['referrer'])

        if User.objects.filter(username=ref_user).exists():

            user = User.objects.create_user(
            username=form.cleaned_data['username']
            )   

            direct = DirectReferral.objects.create(
                name = user,
                referrer = ref_user # New created referrer
            )

            if DirectReferral.objects.filter(referrer=ref_user).exists():

                # Get the referrer of the newly created referrer in DirectReferral database

                indirect = IndirectReferral.objects.create(
                    name = user,
                    referrer = # This should be the referrer of the newly created referrer
                )

How do I make a query or get the referrer of the newly created referrer?

To further understand what I mean please check image below.

I hope you understand my question.

The same way you do it about 5 lines above your comment in your view? — Sayse, Apr 19 '16 at 10:42

Nazif Naz · Accepted Answer · 2016-04-20T10:34:46.743

I guess there is some mistake in the code.

if form.is_valid():

    ref_user = User.objects.get(
    username=form.cleaned_data['referrer'])

    if User.objects.filter(username=ref_user).exists():

        user = User.objects.create_user(
        username=form.cleaned_data['username']
        )   

        direct = DirectReferral.objects.create(
            name = user,
            referrer = ref_user # New created referrer
        )

        if DirectReferral.objects.filter(referrer=ref_user).exists():

            # Here you are checking for something you just created. 
            # I guess this should be 
            # DirectReferral.objects.filter(name=ref_user).exists()

            # Get the referrer of the newly created referrer in DirectReferral database

            indirect = IndirectReferral.objects.create(
                name = user,
                referrer = # This should be the referrer of the newly created referrer
            )

If you intend to find the referrer of the referral user of the currently created user, you could do something like this.

if form.is_valid():

    ref_user = User.objects.get(
    username=form.cleaned_data['referrer'])

    if User.objects.filter(username=ref_user).exists():

        user = User.objects.create_user(
        username=form.cleaned_data['username']
        )   

        direct = DirectReferral.objects.create(
            name = user,
            referrer = ref_user # New created referrer
        )

        try:
            referral_of_ref_user = DirectReferral.objects.get(name=ref_user).referrer
        except DirectReferral.DoesNotExist:
            # Do what needs to be done if direct referral not exist.
            print "No referrer"
            # Get the referrer of the newly created referrer in DirectReferral database
        else:
            indirect = IndirectReferral.objects.create(
                name = user,
                referrer = referral_of_ref_user
            )

EDIT:

By minimal edits to your code:

if form.is_valid():

    ref_user = User.objects.get(
    username=form.cleaned_data['referrer'])

    if User.objects.filter(username=ref_user).exists():

        user = User.objects.create_user(
        username=form.cleaned_data['username']
        )   

        direct = DirectReferral.objects.create(
            name = user,
            referrer = ref_user # New created referrer
        )

        if DirectReferral.objects.filter(name=ref_user).exists():

            # Get the referrer of the newly created referrer in DirectReferral database

            indirect = IndirectReferral.objects.create(
                name = user,
                referrer = DirectReferral.objects.filter(name=ref_user)[0].referrer
            )

Thanks! It worked. Didn't know I could do something like `DirectReferral.objects.get(name=ref_user).referrer`. Do you have a documentation for this kind of query? — Chris Tope, Apr 19 '16 at 18:22
This code is just a usual query. There is a possibility of another exception if name is not unique for `DirectReferral`. You will have to catch `DirectReferral.MultipleObjectsReturned` exception too. — Nazif Naz, Apr 20 '16 at 10:14

Django: Get model field data from a model field data

1 Answers1