Database Keys and Constraints vs SQLPrep

Database Keys and Constraints is an independent study app for learners who want focused practice on relational database design rules, SQL integrity concepts, and exam-style reasoning. Use it to review fundamentals, build practical skills, avoid common pitfalls, and explore advanced concepts across 160 questions. Every question includes an explanation, so you can learn why an answer is right and where mistakes usually happen. Features: - 160 questions on keys, constraints, relationships, and design logic - Spaced repetition using FSRS intervals - Weak-point heatmap to target fragile areas - Daily challenge for steady review - Mock exams for timed practice - Clear explanations for every question - Offline practice, no login required Built for students, interview preparation, database course review, and anyone strengthening SQL schema design knowledge. Independent study app for Database Keys and Constraints practice. Not affiliated with, endorsed by, or sponsored by any company, certification body, exam operator, or vendor. All trademarks belong to their respective owners. Practice offline, no login required.

SQLPrep helps data analyst candidates practice SQL in the minutes between real responsibilities. Work through daily multiple-choice drills, then write real queries against bundled SQLite databases. Every exercise runs locally on your device, so practice is fast, private, and available without an account or internet connection. What you can practice: - SELECT, WHERE, ORDER BY, and LIMIT - Aggregate functions, GROUP BY, and HAVING - JOIN basics and advanced JOIN patterns - Subqueries, CASE, and NULL handling - Window functions - Mixed interview-style SQL problems SQLPrep is built for focused interview preparation. It avoids streak pressure, mascots, ads, subscriptions, and account setup. Instead, you get a local practice log, chapter accuracy percentages, structured query diagnostics, and a clean dark interface designed for serious study. Free practice includes Chapter 1, the first 5 SQLite exercises, and a daily quiz allowance. Unlock Full Practice Library is a one-time purchase that unlocks the full local bank: 200 interview questions and 60 SQLite exercises. No subscription. Download SQLPrep and run your first real query in under a minute — no account, no internet required.