Unable to create object from form - django

Question

After changing the field used as the primary key in a model, I now receive an error when trying to create an object from a form.
I have deleted the sqlite database file, everything in the migrations directory, and performed makemigrations and migrate. I do not believe the problem is with the database, rather something in the code no longer functions the same now that I am not using a custom primary key.
As someone new to Django, I suspect I am missing something fundamental but cannot quite identify what that is.
views.py
#login_required
def job_create(request):
client = request.POST.get('client')
form = JobForm(request.POST or None)
form.fields['client'].initial = Client.objects.get(client_name=client)
if request.method == "POST":
if form.is_valid():
form.save()
return JsonResponse({"Success": True})`
models.py
class Client(models.Model):
client_name = models.CharField(max_length=255, unique=True)
def __str__(self):
return self.client_name
class Job(models.Model):
client = models.ForeignKey(Client, on_delete=models.CASCADE)
job_number = models.CharField(validators=[RegexValidator(regex='^\d{4}$', message='Invalid job number', code='invalid')], max_length=4, unique=True)
job_description = models.CharField(max_length=30)
forms.py
class JobForm(forms.ModelForm):
class Meta:
model = Job
fields = ('client', 'job_number', 'job_description',)`
The above code fails to create and save the object into the database. Below is my attempt to recreate this using the Django shell:
>>> from myproject.models import Client, Job
>>> from myproject.forms import JobForm
>>> client = Client.objects.get(client_name='John')
>>> jobform = JobForm({'client': client, 'job_description':'This is a job description', 'job_number':'4321'})
>>> jobform.errors
{'client': ['Select a valid choice. That choice is not one of the available choices.']}
Database Columns
sqlite> PRAGMA table_info(myproject_job);
0|id|integer|1||1
1|job_number|varchar(4)|1||0
2|job_description|varchar(30)|1||0
3|client_id|integer|0||0
Solution for now
#login_required
def job_create(request):
if request.method == "POST":
client = Client.objects.get(client_name=request.POST.get("client"))
request.POST = request.POST.copy()
request.POST["client"] = client.id
form = JobForm(request.POST)
if form.is_valid():
form.save()
return JsonResponse({"success": "true"})