Computer Science
Database & Storage Challenges
Database & Storage challenges put you inside the work of designing data layers that stay fast and correct under load. You'll develop skills in Data Modeling, Database Schema design, and Domain Modeling, and you'll write SQL with JOINs & Aggregations against PostgreSQL or MySQL.
From there you'll handle the harder edges — Indexing strategy, Query optimization, Replication basics, and Multi-region writes — working through High availability & disaster recovery and Oracle database administration the way data teams actually do. Each challenge you solve earns a verified credential you can share with recruiters.
Recommended Challenges
· PostgreSQL or MySQL Clear- StrategyBeginnerNew
Migrate a Local-Government Records System from MySQL to PostgreSQL
Audit the MySQL schema (around 60 tables) for incompatibilities (case-folding identifiers, ENUM types, TIMESTAMP semantics, character sets). Plan a migration using pgloader for …
- Database Migration
- Postgresql Or Mysql
- Postgresql Or Mysql
Introduction to Database Systems - DesignFoundationalNew
Model and Normalize a Vet-Clinic SaaS Schema
Read the current schema dump (PostgreSQL, around 28 tables, heavily denormalized) and the team's 8 most common reporting queries. Produce an entity-relationship diagram from the…
- Data Modeling
- Normalization
- SQL
Introduction to Database Systems - CodeIntermediateNew
Multi-Tenant SaaS Backend with Postgres Row Security
Design the multi-tenant schema: shared tables with a tenant_id column, indexed appropriately. Write a forward + backward migration (using Drizzle or Prisma). Implement Postgres …
- Multi Tenant Architecture
- Postgresql Or Mysql
- Row Level Security
Web Application Development - AnalysisIntermediateNew
Tune Concurrency Control on a Multi-Tenant OLTP Database
Capture 6 hours of pg_locks + pg_stat_activity snapshots during peak. Identify the top 8 contention hotspots and classify each (row-level conflict, deadlock cycles, FOR UPDATE p…
- Concurrency Control
- Lock Contention
- Postgresql Or Mysql
Advanced Database Systems Practice your coursework on real scenarios.
Every challenge is shaped from real industry context — not generic exercises. The work mirrors what your degree prepares you for.
Why Ewance
- AnalysisBeginnerNew
Add Indexes to a Slow FinTech Reporting Database
Read the 6 reporting queries and capture their EXPLAIN ANALYZE output on staging (a refresh of prod, around 90M rows). Identify the minimum set of indexes that improves all 6 by…
- Indexing Strategy
- Query Optimization
- Explain Analyze
Introduction to Database Systems - CodeIntermediateNew
Java EE Backend for Sustainable Fashion Marketplace
You are to build a RESTful API for EcoThreads using Java EE (Servlets, JPA, and MySQL). The API must support CRUD operations for products (with categories, sustainability rating…
- Java Ee
- REST API Design
- Jpa
Web and Mobile Application Development - CodeIntermediateNew
Build an Indexer for an On-Chain DeFi Analytics Product
Receive the 6 protocols' ABIs + the team's required event coverage spec (around 40 event types). Build a TypeScript indexer using viem + Postgres: subscribe to new blocks via We…
- Blockchain Indexing
- Typescript
- Ethereum
Blockchain and Decentralized Systems Engineering - DesignIntermediateNew
Migrate a Monolithic Database to a Sharded Topology
Analyze schema (32 tables) + query workload (anonymized 7-day pg_stat_statements export) to identify the right shard key per table. Most tables shard on user_id; identify the 4-…
- Database Sharding
- Postgresql Or Mysql
- Vitess
Distributed Systems - Browse challenges
Explore role
Product Manager
Ship product that solves real user problems. Combine user research, prototyping, and stakeholder alignment to turn ambiguous briefs into measurable wins — the role at the centre of modern software teams.
- StrategyIntermediateNew
Design a Multi-Region Blue/Green Database Deployment for an EdTech Platform
Design the migration: source PostgreSQL 14 (primary in São Paulo) to target PostgreSQL 16 (primary in Mexico City, replica in Bogotá). Use logical replication for zero-downtime …
- Blue Green Deployment
- Logical Replication
- Postgresql Or Mysql
DevOps and Secure Deployment - CodeIntermediateNew
Design a Change-Data-Capture Pipeline for an E-Commerce Reseller
Receive the MySQL schema (220 tables), 7 days of binlog samples, and the data team's freshness + correctness requirements. Design the CDC pipeline: Debezium for MySQL binlog cap…
- Change Data Capture
- Debezium
- Kafka Event Streaming
Big Data and Data-Intensive Systems - CodeIntermediateNew
Add Idempotency Keys to a Payment Webhook System
Read the current Go webhook-sender code and 30 days of duplicate-delivery incident logs. Design the idempotency scheme: server-generated key per event (UUID v7 — time-ordered), …
- REST API Design
- Idempotency
- Webhooks
API Design and GraphQL - DesignIntermediateNew
Design a Transactional Schema for a SaaS Order-Provisioning System
Design the schema for orders, quota packs, consumption events, and refunds. Define each critical transaction (buy, consume, refund) with isolation level and locking strategy. Id…
- Precedent Transactions
- Acid
- Isolation Levels
Introduction to Database Systems Build a verifiable portfolio.
Submissions become evidence. Reviewers with shipping experience score against a rubric; the result becomes a credential anyone can verify.
Why Ewance
How it works
From brief to credential, in six steps.
Step 01
Browse challenges aligned to your studies.
Step 02
Accept the one that fits your goals.
Step 03
Work through it with AI Copilot guidance.
Step 04
Submit for structured evaluation.
Step 05
Earn a verified credential.
Step 06
Add it to LinkedIn with one click.
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Sponsor a challenge and meet candidates through actual work.
Industry teams can shape briefs around the skills they hire for, then evaluate students on rubric-scored deliverables — not resumes.