Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add aj-geddes/useful-ai-prompts --skill database-schema-designgit clone --depth 1 https://github.com/aj-geddes/useful-ai-promptsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/database-schema-design)<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/database-schema-design"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/database-schema-design/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/database-schema-design"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/database-schema-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00036 | $0.00534 |
| Opus 5.5 | $0.00014 | $0.00214 |
| Sonnet 5.5 | $0.00007 | $0.00107 |
| Haiku 4.5 | $0.00004 | $0.00053 |
Grade A, and why
database-schema-design scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database Schema Design
Table of Contents
Overview
Design scalable, normalized database schemas with proper relationships, constraints, and data types. Includes normalization techniques, relationship patterns, and constraint strategies.
When to Use
- New database schema design
- Data model planning
- Table structure definition
- Relationship design (1:1, 1:N, N:N)
- Normalization analysis
- Constraint and trigger planning
- Performance optimization at schema level
Quick Start
PostgreSQL - Eliminate Repeating Groups:
-- NOT 1NF: repeating group in single column
CREATE TABLE orders_bad (
id UUID PRIMARY KEY,
customer_name VARCHAR(255),
product_ids VARCHAR(255) -- "1,2,3" - repeating group
);
-- 1NF: separate table for repeating data
CREATE TABLE orders (
id UUID PRIMARY KEY,
customer_name VARCHAR(255),
created_at TIMESTAMP DEFAULT NOW()
);
CREATE TABLE order_items (
id UUID PRIMARY KEY,
order_id UUID NOT NULL,
product_id UUID NOT NULL,
quantity INTEGER NOT NULL,
FOREIGN KEY (order_id) REFERENCES orders(id) ON DELETE CASCADE
);
Reference Guides
Detailed implementations in the references/ directory:
| Guide | Contents |
|---|---|
| First Normal Form (1NF) | First Normal Form (1NF) |
| Second Normal Form (2NF) | Second Normal Form (2NF) |
| Third Normal Form (3NF) | Third Normal Form (3NF) |
| Entity-Relationship Patterns | Entity-Relationship Patterns |
Best Practices
✅ DO
- Follow established patterns and conventions
- Write clean, maintainable code
- Add appropriate documentation
- Test thoroughly before deploying
❌ DON'T
- Skip testing or validation
- Ignore error handling
- Hard-code configuration values
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2mo ago First seen · 86 lines · 36 tokens per session scan A 32d3c79f4bef
database-schema-design is a skill published in the GitHub repository aj-geddes/useful-ai-prompts (376 stars, last pushed 8mo ago), licensed MIT. It adds 36 tokens to every session and 534 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
database-schema-design compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| database-schema-designaj-geddes/useful-ai-prompts | Skill | 376 | 8mo ago | MIT | A | 36 | Claude Code, Codex |
| alloydb-basicsgoogle/skills | Skill | 22k | yesterday | Apache-2.0 | A | 72 | Claude Code, Codex |
| postgresql-table-designwshobson/agents | Skill | 42k | yesterday | MIT | A | 37 | Claude Code |
| db-repairgarrytan/gbrain | Skill | 32k | yesterday | MIT | A | 96 | Claude Code |
| volcengine-rds-postgresqlbytedance/agentkit-samples | Skill | 484 | today | Apache-2.0 | A | 63 | Claude Code, Codex |
| dsqlawslabs/agent-plugins | Skill | 937 | yesterday | Apache-2.0 | A | 246 | Claude Code |
| analyzing-insights-across-teamsPostHog/posthog-foss | Skill | 728 | yesterday | MIT | A | 115 | Claude Code, Codex |