UniqueValidator in drf

user_14547398 0
Viewed 4651

my model has a field:

name = models.CharField(max_length=255, blank=True, null=True)

in serializer, I am trying to raise a unique validation error

name = serializers.CharField(validators=[UniqueValidator(queryset=Department.objects.all(),
                                        message=("Name already exists"))])

but it does not work, because the data comes to the serializer in this format name: {en: "drink"}, in db fields are populated with drink only.

I can raise an error in the create method, but I want to raise the error on the serializer. appreciate any advice. I'm in a hurry. sorry for any inconvenience.

Thanks in advance

django-rest-framework serialization django python
3 Answers

I would highly suggest that you use Django Rest Framework's Serializer Field-Level Validation, which allows you to do custom validation for your field.

like the following:

    name = serializers.CharField()
    ...
    def validate_name(self, value):
        # I assumed that you will that the string value, is a JSON object.
        entered_name = json.loads(value).get('en', None)
        if entered_name and Department.objects.filter(name__exact=entered_name).exists():
            raise serializers.ValidationError("Name already exists!")
        # You need to return the value in after validation.
        return value
     ...
user_94764230

You can do this below your meta class in Serializers.py as it will raise error saying error name must be unique

class Meta:
    model = YourModel

    fields= ('name',) 
    extra_kwargs = {
                'name': {
                    'validators': [
                        UniqueValidator(
                            queryset=YourModelName.objects.all()
                        )
                    ]
                }
            }
user_146892890

i failed to use UniqueValidator so i hacked UniqueTogetherValidator.

Like this;

import it:

from rest_framework.validators import UniqueTogetherValidator

then:

class NameSerializer(serializers.ModelSerializer):
    class Meta:
        model = NameOfModel
        fields = ['id', 'name']
        validators = [
            UniqueTogetherValidator(
                queryset=NameOfModel.objects.all(),
                fields=['name']
            )
        ]

Incase you want the name field to be unique.

Reference: [Here]:https://www.django-rest-framework.org/api-guide/validators/#uniquetogethervalidator

user_87508630
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