CODEWITHSUNDEEP
djangodjango-modelsdjango-rest-framework
msd
msd

Reputation: 75

how to Reverse Relation Serialize N times based on data in database

I want to construct a binary tree like structure(using reverse relation)

an employee with report_to field null is top of the tree(A grade), using reverse serializer I can get their controlled employee list(B grade). but if the B grade employee is controlling some employees then I have to reverse relate that employee list(C grade). some B grade employee may or may not have employee reporting to them. then C grade employee may or may not have employee reporting to them and so on the tree grows till the last employee.

I have an employee table and job_info table

        class employee(models.Model):    
            first_name = models.CharField(max_length = 50)
            last_name = models.CharField(max_length = 50)

        class job_info(models.Model):
            employeeid = models.OneToOneField(employee, on_delete = models.CASCADE)
            report_to = models.ForeignKey(employee, on_delete = models.SET_NULL,related_name = "supervisor", null = True)

if I need to find a limited amount of reverse serializer, I can write the required amount of reverse relation serializer. but in my case, the tree maybe (0 grade) to (N grade). so how do I write a serializer that can handle N number of reverse serializer

Upvotes: 0

Views: 43

Answers (1)

philoj
philoj

Reputation: 488

Quick way to think of this would be SerializerMethodField. Something like:

class Employee(models.Model):
    first_name = models.CharField(max_length = 50)
    last_name = models.CharField(max_length = 50)

class JobInfo(models.Model):
    employee = models.OneToOneField(Employee, related_name='get_job_info')
    supervisor = models.ForeignKey(Employee, related_name='get_sub_employees_info')

class JobTreeSerializer(serializers.ModelSerializer):
    class Meta:
        model = JobInfo
        fields = ('employee', 'sub_employees')

    sub_employees = serializers.SerializerMethodField()

    def get_sub_employees(self, job_info):
        return __class__(job_info.employee.get_sub_employees_info.all(), many=True).data

Note __class__ refers JobTreeSerializer, it would be like nesting the same serializer in itself.

Upvotes: 2

Related Questions