# Stop Raising ValidationError on create() on Serializers

When working with Django and also learning it, I've used to read but also write similar code.

```python
class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ["username", "password", "email"]

    def create(self, validated_data):
        username = validated_data.get("username")

        if username:
            try:
                User.objects.get(username=username)
                raise ValidationError({"user": "This user already exists."})
            except ObjectDoesNotExist:
                pass
        return User.objects.create(**validated_data)
```

What is actually wrong with the code? 
Well, we are raising ValidationError on the `create()` method instead of doing the work of data validation in the `validate()` or the `validate_field()` methods. 🥶

### What are the implications?🤔

First of all, we are violating DRF rules and writing bad code. The fact that there is literally a function we can surcharge to make this task and it's not used is a pretty bad pattern. 

And secondly, performance issues. The validation of the data comes actually before the creation, updating, and deletion of data. 
Writing data validation on the `validate()` or the `validate_field()` methods can make CRUD methods much faster.🚀


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