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- AnalysisBeginnerNew
Index a Slow 90-Million-Row FinTech Reporting Database
Your analysis task is to read the engineering ticket and the six reporting queries in the case file (M1), study the transactions table definition, column statistics, and write w…
- Indexing
- Query Optimization
- Explain Analyze
Open coursework - AnalysisBeginnerNew
Plan and Validate a MySQL-to-PostgreSQL Records Migration
Using the de-identified case record (incident-file-records-office), the representative schema export (mysql-schema-sample), and the anonymized staging extract (staging-records-s…
- Database Migration
- Mysql
- Postgresql
Open coursework - DesignIntermediateNew
Migrate a 6TB Social-Commerce Database to a Sharded Topology
Using the supplied schema specification and the seven-day anonymized query-workload export, decide the correct shard key for each table and justify it from observed access patte…
- Database Sharding
- Postgresql
- Vitess
Open coursework - DesignIntermediateNew
Resolve the Quota Double-Spend: Design Meterly's Order-Provisioning Schema
Working only from the materials provided, reach and defend a database design. Read the de-identified incident record (incident-file) and the business-rules brief (requirements-b…
- Transactions
- Acid
- Isolation Levels
Open coursework Practice your coursework on real scenarios.
Every challenge is shaped from real-world context — not generic exercises. The work mirrors what your degree prepares you for.
Why Ewance
- 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), …
- API Design
- Idempotency
- Webhooks
Open coursework - CodeIntermediateNew
Build a Java EE REST API for the EcoThreads Marketplace
Using the EcoThreads operations file, the sample product catalog export, and the API requirements specification provided to you, design and implement a RESTful backend with Java…
- Java Ee
- REST API
- Jpa
Open coursework - DesignIntermediateNew
Design a Zero-Downtime Multi-Region PostgreSQL Migration for an EdTech Platform
Using the infrastructure inventory (infra-inventory), the database schema sample (schema-subset), the workload metrics (workload-metrics), and the service-level brief (sla-brief…
- Blue Green Deployment
- Logical Replication
- Postgresql
Open coursework - 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
- Row Level Security
Open coursework - 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.
- 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 - 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
Big Data and Data-Intensive Systems - CodeIntermediateNew
Tame Lock Contention on a Shared Property-Manager CRM Database
Working only from the four provided materials, produce a fix-and-prove package. Start with the recorded lock snapshots (lock_snapshots) and the environment case file (db_environ…
- Concurrency Control
- Lock Contention
- Postgresql
Open coursework - DesignFoundationalNew
Redesign a Vet-Clinic SaaS Database to Third Normal Form
Using the current schema dump and the eight most-common reporting queries provided to you, design a replacement database structure for VetLedger. First, produce an entity-relati…
- Data Modeling
- Normalization
- SQL
Open coursework 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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