Error: DoesNotExist: matching query does not exist.

Using Django
1

I want to save user details from a custom form which has OneToOne connection with User Model. While i try to save it I am getting this error.

UserAuthentication matching query does not exist

The below line is the line from which i getting the above error

userauth_obj = UserAuthentication.objects.get(U_User=user_obj)

views.py

@login_required(login_url='login')
def UserAuthform(request):

    if request.method == 'POST':

        user = request.user.username
        auth = request.POST.get('D_Auth')
        chid = request.POST.get('D_ChID')
        utyp = request.POST.get('U_Type')
        loss = request.POST.get('N_Loss')

        if auth is None:
            messages.success(request, 'Authentication Key Must be Entered')
            return redirect('UserAuthForm')

        elif chid is None:
            messages.success(request, 'Channel ID Must be Entered')
            return redirect('UserAuthForm')

        elif UserAuthentication.objects.filter(D_Auth=auth).exists():
            messages.success(request, 'Authentication key in Use')
            return redirect('UserAuthForm')

        elif utyp is None:
            messages.success(request, 'User Type Must Be Selected')
            return redirect('UserAuthForm')

        else:
            user_obj = User.objects.get(username=user)

            userauth_obj = UserAuthentication.objects.get(U_User=user_obj)

            userauth_obj.D_Auth = auth
            userauth_obj.D_ChID = chid
            userauth_obj.U_Type = utyp
            userauth_obj.N_Loss = loss
            userauth_obj.save()

            return redirect('Home')

    return render(request, 'registration/userauthform.html')

models.py

class UserAuthentication(models.Model):
    U_User = models.OneToOneField(
        User,
        on_delete=models.CASCADE,
        primary_key= True,
    )

    D_Auth = models.CharField(max_length=100, unique=True)
    D_ChID = models.PositiveIntegerField(null=False)
    U_Type = models.CharField(max_length=7)
    N_Loss = models.BooleanField(null=False, default=False)
    U_PreM = models.BooleanField(null=False, default=False)

    def __str__(self):
        return self.U_User.username

userauthform.html

{% extends "index.html" %}
{% block content %}

<div class="container">
        <form method="post" class="form" id="form">
        {% csrf_token %}

        <h1>Register</h1>

        {% if messages %}
            {% for message in messages %}
                <div class="alert alert-info">
                    {{ message }}
                </div>
            {% endfor %}
        {% endif %}

        <div class="form-group">
            <label for="D_Auth">Discord Authentication Key</label>
            <input type="text" name="D_Auth" id="D_Auth" class="form-control">
        </div>

        <div class="form-group">
            <label for="D_ChID">Discord Channel Id</label>
            <input type="text" name="D_ChID" id="D_ChID" class="form-control">
        </div>

        <div class="form-group">
            <label for="U_Type">Player Type</label>
            <select name="U_Type" id="U_Type" class="form-control">
                <option value="Normal">Normal Player</option>
                <option value="Patron">Patron Player</option>
            </select>
        </div>

        <div class="form-group">
            <label for="N_Loss">No Loss</label>
            <input type="checkbox" name="N_Loss" id="N_Loss" class="form-control">
        </div>

        <button class="btn btn-success mt-3" type="submit">Submit</button>

        <a href="{% url 'register' %}">Create a Account</a>
        <a href="{% url 'forgetpass' %}">Reset My Password</a>

        </form>
</div>

{% endblock content %}
2

Hi @GoAmeer030, the clue is in the error message. UserAuthentication matching query does not exist. The query is .get(U_User=user_obj). Breaking it down it means that there is no UserAuthentication instance that has the propert U_User set to the user_obj instance. This likely means that a user was created, but the corresponding UserAuthentication was not. I’m not entirely sure of the purpose of this view, but you could handle it with update_or_create:

userauth_obj, created = UserAuthentication.objects.update_or_create(
     U_User=user_obj,
     defaults={
            "D_Auth":  auth,
            "D_ChID":  chid,
            "U_Typ":  utyp,
            "N_Loss":  loss,
     }
)
1 Like
3

Thanks bro it works perfectly fine. Please take a look on this too Link. And Please tell where you find these functions and their uses. Thankyou

4

For me it’s been reading the docs occasionally combined with repeated usage of the functions that caused me to remember that they exist.

2 Likes