database-schema-design

Database schema design for PostgreSQL/MySQL with normalization, relationships, constraints. Use for new databases, schema reviews, migrations, or encountering missing PKs/FKs, wrong data types, premature denormalization, EAV anti-pattern.

Install with Tessl CLI

npx tessl i github:secondsky/claude-skills --skill database-schema-design

What are skills?

Review — 92%

Does it follow best practices?

Evaluation — 98%

Agent success when using this skill

Validation — 10 / 11 Passed

Validation for skill structure

SKILL.md

Review

Evals

Evaluation results

100%

12%

E-commerce Platform Database Schema

Primary keys, foreign keys, indexes, and audit columns

Criteria

Without context

With context

UUID primary keys

100%

All tables have PKs

100%

Foreign keys explicit

100%

ON DELETE/UPDATE specified

100%

FK indexes present

100%

Audit columns all tables

50%

100%

TIMESTAMPTZ for timestamps

100%

NOT NULL on required fields

100%

Bounded VARCHAR lengths

100%

DECIMAL for money

100%

CHECK for enum status

100%

CHECK for numeric ranges

100%

Without context: $0.1652 · 34s · 8 turns · 9 in / 2,358 out tokens

With context: $0.3738 · 59s · 16 turns · 15 in / 3,471 out tokens

95%

-3%

Content Publishing Platform Schema

Normalization, EAV avoidance, naming conventions, soft deletes

Criteria

Without context

With context

No EAV pattern

100%

JSONB for metadata

100%

70%

GIN index on JSONB

100%

Soft delete pattern

100%

Junction table for M:M

100%

Table naming convention

100%

FK column naming

100%

Index naming convention

100%

Normalized 3NF

100%

NOT NULL required fields

100%

Bounded VARCHAR

100%

TIMESTAMPTZ audit columns

75%

No polymorphic comments

100%

Without context: $0.1940 · 50s · 7 turns · 8 in / 3,613 out tokens

With context: $0.4200 · 1m 9s · 15 turns · 3,669 in / 3,982 out tokens

100%

11%

Project Management SaaS Schema

Cascade rules, updated_at triggers, BOOLEAN types, data types

Criteria

Without context

With context

CASCADE on org delete

100%

CASCADE on project delete

100%

SET NULL on user delete

100%

updated_at trigger function

100%

Trigger on each table

100%

BOOLEAN for flags

100%

CHECK on status enum

70%

100%

CHECK on priority range

100%

UUID primary keys

100%

FK indexes present

100%

TIMESTAMPTZ audit columns

100%

NOT NULL on required fields

100%

Without context: $0.1454 · 32s · 7 turns · 8 in / 2,096 out tokens

With context: $0.4458 · 1m 12s · 19 turns · 18 in / 4,113 out tokens

Evaluated: about 6 hours ago
Agent: Claude Code

Table of Contents

E-commerce Platform Database Schema Content Publishing Platform Schema Project Management SaaS Schema

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