database-architect

database-architect is a skill for Claude Code, Codex from tranhieutt/software_development_department. It costs 44 tokens per session (1,192 once invoked), scanned A, original, MIT.

A guide to relational and NoSQL database design, including schemas, indexes, migrations, caching, and technology selection.

In plain words
What is it for?
Use it to choose a database, model data, design indexes, plan migrations, and record architecture decisions.
Why use it?
It helps turn application access needs into a database structure with planned performance and migration paths.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/tranhieutt/software_development_department/database-architect
Any agent
npx skills add tranhieutt/software_development_department --skill database-architect
Clone the repo
git clone --depth 1 https://github.com/tranhieutt/software_development_department

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for database-architect

README.md
[![agentmods](https://agentmods.dev/badge/skills/tranhieutt/software_development_department/database-architect.svg)](https://agentmods.dev/skills/tranhieutt/software_development_department/database-architect)
Your own site
<a href="https://agentmods.dev/skills/tranhieutt/software_development_department/database-architect"><img src="https://agentmods.dev/badge/skills/tranhieutt/software_development_department/database-architect.svg" alt="Measured on agentmods" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,192 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00044 $0.01192
Opus 5 $0.00022 $0.00596
Sonnet 5 $0.00009 $0.00238
Haiku 4.5 $0.00004 $0.00119

Measured 5d ago against content hash b54bfc7c3f08, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

database-architect 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 5d 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.

.claude/skills/database-architect/SKILL.md · 122 lines

How it starts

The opening of the file, as written. The whole thing — 122 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Database Architect

Workflow

  1. Understand domain: Access patterns, scale targets, consistency needs, compliance requirements
  2. Select technology: Match DB type to workload (see matrix below)
  3. Design schema: Normalization level, relationships, constraints, temporal data strategy
  4. Plan indexing: Query-pattern-driven index design (not speculative)
  5. Design caching: Layer strategy with invalidation
  6. Plan migration: Zero-downtime approach, rollback procedures
  7. Document decisions: ADR with rationale and trade-offs

Technology selection matrix

Workload Primary choice Alternative
OLTP / relational PostgreSQL MySQL
Flexible documents MongoDB Firestore
Key-value / cache Redis DynamoDB
Time-series / IoT TimescaleDB InfluxDB
Analytical / OLAP ClickHouse BigQuery
Graph relationships Neo4j Amazon Neptune
Full-text search Elasticsearch Meilisearch
Globally distributed CockroachDB Google Spanner
Multi-tenant SaaS PostgreSQL (row-level security) Schema-per-tenant

Decision rule: Choose PostgreSQL by default; deviate only when access patterns demand it with documented rationale.

Non-obvious rules

  • Normalize first, denormalize with evidence — premature denormalization creates update anomalies; measure before optimizing
  • Index on access patterns, not columns — index the query, not the table; one slow-query explain plan is worth more than any speculation
  • Foreign keys always — letting the application enforce referential integrity is a data corruption waiting to happen
  • JSONB for flexible attributes, not as a schema escape hatch — use JSONB when fields are genuinely variable; not to avoid schema discipline
  • Partition late — partition tables only once you have row counts >50M or explicit I/O pressure; early partitioning adds complexity with zero benefit
  • UUID v7 over v4 — v7 is time-ordered (k-sortable), avoids index fragmentation, same uniqueness guarantees

Read the full file on GitHub · 122 lines

Changes

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.

  1. 5d ago First seen · 122 lines · 44 tokens per session scan A b54bfc7c3f08

Subscribe to this mod's changes

database-architect is a skill published in the GitHub repository tranhieutt/software_development_department (71 stars, last pushed 3mo ago), licensed MIT. It adds 44 tokens to every session and 1,192 once invoked, about $0.0002 per session on Opus 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 2026-08-30.