Integration TrailsINTEGRATION/TRAILS
FORGENewARTICLESMODULESCHALLENGESLEADERBOARDPRICINGABOUTDASHBOARD
INTEGRATION/TRAILS

Stop Reading Theory. Start Solving Problems.

// Built by practitioners
// PlatformModulesChallengesLeaderboardTrailsArticles
// ConnectNewsletterYouTubeTikTokAbout Us
// SupportHelp & SupportContactPrivacy Policy
© 2026 — Integration TrailsContent — CC BY-NC-SA | Code — MIT LicenseVER:2026-08-27-815c939
Challenges/build-hierarchical-bom-from-flat-database-results·DataWeave·EXPERT
DataWeaveEXPERT

Build Hierarchical BOM from Flat Database Results

Transform flat database records into a nested JSON hierarchy using a recursive DataWeave function. You will learn to build tree structures by filtering parent-child relationships and implementing strict base cases with `isEmpty()` to prevent infinite recursion.

#jdbc#recursion
BY @patryk_bandurski
Community rating
—
Not rated yet
Sign in to rate
DWL
// READY TO BEGIN

Make it
count.

  • 3 attempts on every challenge
  • XP points & leaderboard scored
  • Public profile & shared trail
  • Newsletter weekly with API replay
Sign Up Free →Already a member → Sign in
// Built by practitioners

The fastest way
to learn integration.

Every challenge ships with a real-world payload, a graded test suite, and a walkthrough by a practitioner. No surface-level theory — just problems, solved.

…Challenges
…Modules
// You're reading in preview mode

You can read everything.
Coding requires an account.

🔒 IDE locked · sign in to enable
%dw 2.0
output application/json
---
payload
// Sign up to run, submit, and earn XP on this challenge
// Be first to rate this challenge!SCROLL TO READ ↓

The fastest way
to learn integration.

01.
Production payloads
Real CSV/JSON/XML you'll meet on day one — null fields, mixed casing, partial records.
02.
Design problems
What practitioners actually solve — null-safety, idempotency, retries, batch boundaries.
03.
Edge cases that break
Empty arrays, type coercion, deeply nested transforms, locale-specific dates.
…
CHALLENGES
…
MODULES
// Free forever · No credit card

Sign up.
Then code.

Free accounts get 3 attempts per challenge, full XP, and your trail progress synced across devices.

▶ Sign up free →Have an account? Sign in →
// WHAT YOU'LL BUILDHOW IT WORKS ↓
01.
Live DataWeave editor
Real DWL 2.0 IDE with helpers, modules, syntax highlighting.
02.
Test cases run on real runner
Same Go runner used in prod. Diffs show exactly which fields fail.
03.
3 graded attempts
Submit when you're ready. Score persists. Solution unlocks after pass or last attempt.
04.
Helpers & multi-module DWL
Bring in reusable %dw modules. Import, export, compose.
05.
XP & leaderboard
Points + XP awarded per challenge. Trail progress synced.
06.
Production-style payloads
Real CSV/JSON/XML — null fields, mixed casing, partial records.