# Database Keys and Constraints — Practice SQL Rules Daily

> Practice SQL Rules Daily (iPhone/iPad app by Tsuyoshi Sezaki.)

- Source: https://appshunter.io/ios/app/database-keys-and-constraints/id6773622183 (this page in markdown: same URL + `.md`)
- Developer: [Tsuyoshi Sezaki](https://appshunter.io/developer/1886356149)
- Category: Education
- Price: Free
- Age rating: 4+
- Requires: iOS 15.1 · 38 MB
- Languages: American English
- Released: 2026-05-30
- Data updated: 2026-07-06
- User reviews in markdown: https://appshunter.io/ios/app/database-keys-and-constraints/id6773622183/reviews.md

## What is Database Keys and Constraints?

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.


## Version history (last 1 release)

### 1.0 — 2026-05-30

No release notes.

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All apps by Tsuyoshi Sezaki: https://appshunter.io/developer/1886356149

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-06.*