CODEWITHSUNDEEP
django-rest-frameworkdjango-viewsdjango-serializer
steden
steden

Reputation: 21

Return row where column is NULL

I've created an API with rest_framework and can receive API calls that updates the database, but I can't figure how to query the database and return any row where the field "Endtime" is NULL.

In the function below I'm updating the database with the received JSON-data and this fails to return any result where the value is NULL for Endtime. Below is the error I get. How should I write the view to return rows where endtime column is NULL?

ValidationError at /durationupdate/ ['“NULL” value has an invalid format. It must be in YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format.'] Request Method: POST Request URL: http://127.0.0.1:8000/durationupdate/ Django Version: 4.1.1 Exception Type: ValidationError Exception Value:
['“NULL” value has an invalid format. It must be in YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format.']

views.py `

@api_view(['POST', 'GET'])
def durationUpdate(request):
    if request.method == 'POST':
        serializer = RigstateSerializer(data=request.data)              
        wherenull = Rigstate.objects.get(endtime='NULL')
        wherenullserializer = DurationSerializer(wherenull, many=True)
        if serializer.is_valid():                                       
            serializer.save()                               
        return Response(wherenullserializer.data)

`

models.py `

class Rigstate(models.Model):
    rigname = models.CharField(max_length=255)
    rigmode = models.IntegerField(default=0)
    starttime = models.DateTimeField()
    endtime = models.DateTimeField(blank=True, null=True)
    duration = models.IntegerField(default=0)

    def __str__(self):
        return self.rigname

`

I've tried changing from 'NULL' to NULL but then I get a different error

Upvotes: 1

Views: 42

Answers (2)

steden
steden

Reputation: 21

Changed name to a more appropriate (DurationList)

views.py

@api_view(['GET'])
def durationList(request):
    if request.method == 'GET':
        duration = Rigstate.objects.values_list('endtime')
        wherenullserializer = DurationSerializer(duration, many=True)
        return Response(wherenullserializer.data)

Most changes were in serializers.py

class DurationSerializer(serializers.ModelSerializer):
    class Meta:
        model = Rigstate
        endtime = serializers.DateTimeField(allow_null=True) 
        fields = ('endtime',)

Now I only get columns where entime is null, and only the endtime value

Upvotes: 1

Muhammad Hassan
Muhammad Hassan

Reputation: 14391

You should your endtime write only and override to_represenation method like this.

class RigstateSerializer(serializer.ModelSerializer):
     class Meta:
         model = Rigstate
         fields = '__all__'
         extra_kwargs = {'endtime': {'write_only': True}}
     
     def to_representation(self, instance):
          data = super().to_representation(instance)
          if instance.endtime:
               data['endtime'] = instance.endtime.strftime(#write you required format here)
          return data

Upvotes: 1

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