What is meant by the related_query_name field in Django and how is it used in modeling relationships?

In Django, the related_query_name field is used in model relationships (ForeignKey, ManyToManyField, OneToOneField) and sets the name for reverse access to related objects when building queries.

By default, Django generates the reverse name automatically, but sometimes you need to specify a more convenient or unique name, especially if the model has multiple relations to the same model.

Example:

class Author(models.Model):
    name = models.CharField(max_length=100)

class Book(models.Model):
    author = models.ForeignKey(Author, on_delete=models.CASCADE, related_query_name='book')

Now you can make queries like:

Author.objects.filter(book__title__icontains='Python')

Here, book is the related_query_name, allowing to refer to the author's books in filters.

Thus, related_query_name helps to conveniently and explicitly name reverse relations for ORM queries.