[Answered ]-Retrieve data from models having reverse relationship in django rest

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Before I was using nested serializer but nested serializer slow down its response.

The nested serializer itself does not slow down the response, this simply because it will result in an N+1 problem: you need to load the related data in bulk.

You can use .prefetch_related(…) [Django-doc] for this, so:

Section.objects.prefetch_related('sections')

This will load SubSections of the selected Section(s) in bulk.

It however does not make much sense to use 'sections' for the related_name=… parameter [Django-doc], since this is the name of the relation in reverse. You thus might want to rename this to:

class SubSection(models.Model):
    section = models.ForeignKey(
        Section,
        related_name='subsections',
        on_delete=models.PROTECT
    )
    sub_title= models.TextField()

and thus prefetch with:

Section.objects.prefetch_related('subsections')
👤willeM_ Van Onsem

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