Drills

Use foreign keys and cascade rules safely

Explains referential integrity, cascade delete trade-offs, restrict behavior, soft deletes, and operational safety.

Concept questionEasy~5 min

Use GROUP BY and HAVING for business counts

Explains aggregate queries, grouping keys, filters before and after aggregation, and business-count correctness.

Use If-Match preconditions to prevent lost updates

Connects HTTP preconditions to atomic database concurrency checks and honest 412 or 428 API behavior.

.NETASP.NET Core

Architecture scenarioMedium~10 min

Use immutable snapshots instead of shared mutable state

Redesigns read-heavy shared state so readers observe a complete version without coordinating every access through a lock.

.NETC#

Comparison questionEasy~5 min

Use logs, metrics, and traces for API diagnosis

Explains the different diagnostic roles of logs, metrics, and traces during backend production issues.

.NETApplication InsightsASP.NET CoreOpenTelemetry

ASP.NET CoreNext.jsReactTypeScript

Use Next.js route handlers as an API boundary

Explains route handlers as a frontend server boundary for cookies, API adaptation, auth, and backend calls.

Architecture scenarioMedium~10 min

Use OpenAPI as an API contract

Use OpenAPI for API design, client integration, testing, and contract review in ASP.NET Core services.

.NETASP.NET CoreC#

Use optimistic concurrency with rowversion

Prevents lost updates with an original rowversion predicate, maps zero affected rows to an explicit conflict, and defines user, retry, aggregate, and API precondition behavior.

Use read models for complex API screens

Explains read models for complex API screens with practical .NET data-access examples and production trade-offs.

.NETC#EF CoreSQL

.NETASP.NET CoreRedisStackExchange.Redis

Use Redis counters for API rate limiting

Explains Redis-backed rate-limit counters, atomic increments, windows, identity keys, and fallback behavior.

Concept questionHard~9 min

Use Redis locks only with clear lease boundaries

Explains the risks of Redis-based distributed locks and when database constraints, queues, or idempotency are safer.

.NETASP.NET CoreRedisStackExchange.Redis

Comparison questionEasy~5 min

Use, Run, and Map in the ASP.NET Core middleware pipeline

Explains middleware continuation, terminal delegates, path branches, short-circuiting, and two-way request and response flow.

.NETASP.NET CoreC#

Use security headers, TLS, and cookie flags correctly

Explains HTTPS, HSTS, secure cookies, HttpOnly, SameSite, no-store, and practical API/browser security hardening.

.NETASP.NET CoreJWT

.NETApplication InsightsASP.NET CoreOpenTelemetry

Use structured logs without leaking sensitive data

Explains structured logging fields, safe context, redaction, event naming, and avoiding secret or personal-data leaks.

Use Suspense and streaming boundaries in Next.js

Explains how Suspense boundaries stream useful page regions while coordinating loading, errors, and data ownership.

Next.jsReactTypeScript

.NETAmazon SQSAzure Service BusRabbitMQ

Use the inbox pattern to deduplicate consumed messages

Makes consumer-side deduplication atomic with the business change while supporting concurrent delivery, retention, replay, and failed processing.

Use unique constraints for business rules

Makes business uniqueness race-safe with the exact database key, while handling normalization, tenant scope, nulls, soft deletion, rollout cleanup, and stable API conflicts.

Use unknown safely at TypeScript boundaries

Explains why external data needs runtime validation even when the application uses TypeScript.

TypeScript

Use window functions for latest row per group

Uses ROW_NUMBER with deterministic partition ordering to return one complete latest row per group, then evaluates index support, tie semantics, scale, and read-model alternatives.