DataLoader (N+1)

The Problem

Fetching a list of posts and then fetching the author for each post in a loop causes the “N+1 Problem”:

posts = await post_repo.get_multi(session) # 1 Query
for post in posts:
    # N Queries!
    author = await user_repo.get(session, post.user_id)

FluxCRUD integrates the DataLoader pattern to batch these requests automatically.

Use repo.get_many_by_ids():

user_ids = [p.user_id for p in posts]
# 1 Query (SELECT ... WHERE id IN (...))
authors = await user_repo.get_many_by_ids(user_ids)

Internally, FluxCRUD collects all these IDs and fires a single optimal SQL query.