How to get relate model without nested in Django rest framework?-CodePudding

How to get a json with relate model but without nested in Django rest framework?

Code :

Models, Session and Athlete, Athlete models has foreign key relationship with Session

class Session(models.Model):
    Id = models.AutoField(primary_key=True)
    SessionNo = models.SmallIntegerField()
    WinTeam = models.SmallIntegerField(null=True)

class Athlete(models.Model):
    Id = models.AutoField(primary_key=True)
    Name = models.CharField(max_length=6)
    Age = models.SmallIntegerField()
    Session = models.ForeignKey(Session, on_delete=models.CASCADE, related_name='athletes')
    Status = models.SmallIntegerField()

Serializers

class SessionSerializer(serializers.ModelSerializer):
    class Meta:
        model = Session
        fields = '__all__'

class AthleteSerializer(serializers.ModelSerializer):
    Session = SessionSerializer(read_only=True)

    class Meta:
        model = Athlete
        fields = ('Age', 'Status', 'Session')

And views:

def all_athletes(request):
    """
    Get all athletes list
    """
    queryset = Athlete.objects.all().select_related()
    serializer = AthleteSerializer(instance=queryset, many=True)
    return Response(serializer.data)

And the API result is :

[
    {
        "Age": 38,
        "Status": 1,
        "Session": {
            "Id": 13,
            "SessionNo": 1,
            "WinTeam": null
        }
    },
    {
        "Age": 26,
        "Status": 1,
        "Session": {
            "Id": 13,
            "SessionNo": 1,
            "WinTeam": null
        }
    },
    {
        "Age": 35,
        "Status": 2,
        "Session": {
            "Id": 13,
            "SessionNo": 1,
            "WinTeam": null
        }
    }
]

It works to get relate model, but I want relate models show without nested, how to do to fit my expectation ?

I expect the API result:

[
    {
        "Age": 38,
        "Status": 1,
        "Id": 13,
        "SessionNo": 1,
        "WinTeam": null
    },
    {
        "Age": 26,
        "Status": 1,
        "Id": 13,
        "SessionNo": 1,
        "WinTeam": null
    },
    {
        "Age": 35,
        "Status": 2,
        "Id": 13,
        "SessionNo": 1,
        "WinTeam": null
    }
]

CodePudding user response：

You could try SerializerMethodFields....

class AthleteSerializer(serializers.ModelSerializer):
    Id = serializers.SerialierMethodField(read_only=True)
    SessionNo = serializers.SerialierMethodField(read_only=True)
    WinTeam = serializers.SerialierMethodField(read_only=True)

    class Meta:
        model = Athlete
        fields = ('Age', 'Status', 'Id', 'SessionNo', 'WinTeam')
    
    def get_Id(self, obj):
        return obj.Session.id
    
    def get_SessionNo(self, obj):
        return obj.Session.SessionNo
    
    def get_WinTeam(self, obj):
        return obj.Session.WinTeam

And then remember to prefetch the Session relationship(s) in your view's queryset or else it will hit the database multiple times for those multiple fields

CodePudding user response：

You can override to_representation() in AthleteSerializer as well. With that you do not need SerialierMethodField.

def to_representation(self, value):
   ref = super().to_representation(value)
   session = ref.pop("Session")
   ref.update(**session)
   return ref