In django,Use one field from one model in other model

Question

I'm trying to use auth_method field from MethoID model in AgentDetails Model.But when I enter the value of primary key id in serializer for authen_method it is not being validated.

Models:

 class AuthMethodID(models.Model):
    auth_method = models.CharField(max_length=50, default="Google")

    def __str__(self):
        return self.auth_method

class AgentDetail(models.Model):
    authen_method = models.ForeignKey(AuthMethodID, on_delete=models.CASCADE)

Serializer:

class AgentSerializer(serializers.ModelSerializer):
class Meta:
    model = AgentDetail
    fields = [
        "authen_method",
    ]

and in views I use POST request.

Views:

    @api_view(["POST"])
def create_agent(request):
    if request.method == "POST":
        serializer = AgentSerializer(data=request.data, many=False)
        if serializer.is_valid():
            serializer.save()
            return Response(status=status.HTTP_200_OK)
        error = Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
        return error

I send this as request body, cause I added just one value in AuthMethodID model auth_method field(Google),so it could use its primarykey value as input in request body. There are other fields in AgentDetail model which I use them in request body but I have only one field in AuthMethodID model which I intend to use in requestbody as primarykey value.

{      
        "authen_method": 1,
}

Error:

Answer 1

When you send the following response as request body you must make sure the foreign model instance ( here, auth_method with id 1 ) already exists. Create a instance of AuthMethodID model first. Then again try to post the child model AgentDetail instance.

   {
    "authen_method": 1
   }