sending queryset in serialzerm ethod field drf code example

Example 1: serializers.validationerror django

class HighScoreSerializer(serializers.BaseSerializer):
    def to_internal_value(self, data):
        score = data.get('score')
        player_name = data.get('player_name')

        # Perform the data validation.
        if not score:
            raise serializers.ValidationError({
                'score': 'This field is required.'
            })
        if not player_name:
            raise serializers.ValidationError({
                'player_name': 'This field is required.'
            })
        if len(player_name) > 10:
            raise serializers.ValidationError({
                'player_name': 'May not be more than 10 characters.'
            })

        # Return the validated values. This will be available as
        # the `.validated_data` property.
        return {
            'score': int(score),
            'player_name': player_name
        }

    def to_representation(self, instance):
        return {
            'score': instance.score,
            'player_name': instance.player_name
        }

    def create(self, validated_data):
        return HighScore.objects.create(**validated_data)

Example 2: how to add methods to manuplate the model in serializers

from django.db import models
from django.contrib.auth.models import User

class UnivStudent(models.Model):
    """
    A class based model for storing the records of a university student
    Note: A OneToOne relation is established for each student with User model.
    """
    user = models.OneToOneField(User)
    subject_major = models.CharField(name="subject_major", max_length=60)