[VWWHFSfQ]

Django will do something similar (possibly a little more elegantly) if one is familiar with how to use the Prefetch APIs [1]:

    Post.objects.order_by("-created_at").prefetch_related(
        Prefetch(
            "comments",
            queryset=Comment.objects.annotate(
                vote_count=Count("votes")
            ),
        )
    )[:3]

This will generate the following two queries:

    SELECT
        "post"."id",
        "post"."created_at",
        "post"."title",
        "post"."content"
    FROM "post"
    ORDER BY "post"."created_at" DESC
    LIMIT 3;

    SELECT
        "comment"."id",
        "comment"."post_id",
        "comment"."content",
        COUNT("vote"."id") AS "vote_count"
    FROM "comment"
    LEFT OUTER JOIN "vote"
        ON ("comment"."id" = "vote"."comment_id")
    WHERE "comment"."post_id" IN (3, 2, 1)
    GROUP BY
        "comment"."id",
        "comment"."post_id"

[1] https://docs.djangoproject.com/en/4.1/ref/models/querysets/#...

[chc]

Personally, I find the Rails version a bit more elegant because it is declarative, reusable and composable, while Django's approach is a more utilitarian "just write the dang query when you want it." But both are a great illustration of how a well-designed ORM can give you the tools you need to get good performance.

[saila]

You can do the same kind of thing in Django. The approach is a little different, but it's the same basic idea.

https://docs.djangoproject.com/en/4.1/topics/db/managers/#cu...