Django 2.2 error - Integrity Error, NOT NULL constraint failed - django

Question

I have a sample Django 2.2 project that has a search bar in the top right corner of the nav bar (taken from the Bootstrapers):
navbar.html:
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="/">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="/">Home <span class="sr-only">(current)</span></a>
</li>
{% if user.is_authenticated %}
<li class="nav-item">
<a class="nav-link" href="/search/">Search</a>
</li>
...
{% endif %}
<li class="nav-item">
<a class="nav-link" href="/a/">A</a>
</li>
<li class="nav-item">
<a class="nav-link" href="/b/">B</a>
</li>
</ul>
<form class="form-inline my-2 my-lg-0" action = '/search/'>
<input class="form-control mr-sm-2" type="search" name="q" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
It returns "You searched for [search argument]" to the url '/search/' and works fine. I would like to bring it from the nav bar under the 'Search' menu in the nav bar. I have the following:
searches/models.py
from django.db import models
from django.conf import settings
# Create your models here.
class SearchQuery(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, blank = True, null=True, on_delete=models.SET_NULL)
query = models.CharField(max_length=220)
timestamp = models.DateTimeField(auto_now_add=True)
searches/views.py:
from django.shortcuts import render
from django.contrib.auth.decorators import login_required
from django.contrib.admin.views.decorators import staff_member_required
from .models import SearchQuery
# Create your views here.
#login_required
# staff_member_required
def search_view(request):
query = request.GET.get('q', None)
user = None
if request.user.is_authenticated:
user = request.user
SearchQuery.objects.create(user=user, query=query)
context = {"query": query}
return render(request, 'searches/view.html',context)
searches/templates/searches/view.html:
{% extends "base.html" %}
{% block content %}
{% if user.is_authenticated %}
<form action = '/search/'>
<input type="search" name="q" aria-label="Search">
<button type="submit">Search</button>
</form>
<div class='row'>
<div class='col-12 col-8 mx-auto'>
<p class='lead'>You searched for {{ query }}</p>
</div>
</div>
{% endif %}
{% endblock %}
When I search from the search bar in the navigational pane, it returns the argument. But when I want to run the search from the search bar and click on the Search tab, I get this:
IntegrityError at /search/
NOT NULL constraint failed: searches_searchquery.query
...
...searches\views.py in search_view
SearchQuery.objects.create(user=user, query=query)
Why am I getting this ?
EDIT:
After making this change in searches/views.py:
query = request.POST.get('q', None)
I get this error in the runtime:
django.db.utils.IntegrityError: NOT NULL constraint failed: searches_searchquery.query
and in the browser: