How to check if a record already exists or not in database in DRF? - orm

Question

I am working on DRF. I am creating an API of POST request that overriding its features. I want to add one functionality if a particular field value already exists in DB then, user cannot create post request and instead of it getting a message that he couldn't do it.
views.py
class PizzaOrderViewSet(viewsets.ModelViewSet):
http_method_names = ['get', 'put', 'patch', 'post']
def create(self, request, *args, **kwargs):
data = request.data
order = PizzaOrder.objects.create(
name=data['name'], flavours=data['flavours'],
number=data['number'], size=data['size'],
customer_name=data['customer_name'],
customer_address=data['customer_address']
)
order.save()
serializer = PizzaOrderSerializer(order)
return Response(serializer.data)
serializers.py
class PizzaOrderSerializer(serializers.ModelSerializer):
class Meta:
model = PizzaOrder
validators = [
UniqueTogetherValidator(
queryset=PizzaOrder.objects.all(),
fields=['name', 'flavours', 'size', 'customer_name', 'customer_address'],
message='This field should be unique'
)
]
models.py
from django.db import models
from datetime import datetime
FLAVOURS_CHOICE = (
('Margarita', 'Margarita'),
('Marinara', 'Marinara'),
('Salami', 'Salami'),
)
SIZE_CHOICE = (
('Small', 'Small'),
('Medium', 'Medium'),
('Large', 'Large'),
)
STATUS_CHOICE = (
('Open', 'Open'),
('Accepted', 'Accepted'),
('Preparing', 'Preparing'),
('OnWay', 'OnWay'),
('Delivered', 'Delivered'),
)
class PizzaOrder(models.Model):
name = models.CharField(max_length=50, blank=False)
flavours = models.CharField(max_length=20, choices=FLAVOURS_CHOICE)
quantity = models.IntegerField()
size = models.CharField(max_length=10, choices=SIZE_CHOICE)
customer_name = models.CharField(max_length=30, blank=False)
customer_address = models.TextField(blank=False)
ordered_time = models.DateTimeField(default=datetime.now, editable=False)
status = models.CharField(max_length=20, choices=STATUS_CHOICE, default='Open')
def __str__(self):
return self.name
class Meta:
ordering = ['-ordered_time']
unique_together = ('name', 'flavours', 'quantity', 'size')
How could I achieve this?