database-documentation-gen

name	database-documentation-gen
description	Process use when you need to work with database documentation. This skill provides automated documentation generation with comprehensive guidance and automation. Trigger with phrases like "generate docs", "document schema", or "create database documentation".
allowed-tools	Read, Write, Edit, Grep, Glob, Bash(psql:*), Bash(mysql:*), Bash(mongosh:*)
version	1.0.0
author	Jeremy Longshore <[e-mail]>
license	MIT
compatible-with	claude-code, codex, openclaw
tags	["database","database-documentation"]

Database Documentation Generator

Overview

Generate comprehensive database documentation by introspecting live PostgreSQL or MySQL schemas, extracting table structures, column descriptions, relationships, indexes, constraints, stored procedures, and views. Produces human-readable documentation in Markdown format including entity-relationship descriptions, data dictionary, and column-level metadata.

Prerequisites

• Database credentials with read access to information_schema, pg_catalog (PostgreSQL), or system tables (MySQL)
• psql or mysql CLI for executing introspection queries
• Target output directory for generated documentation files
• Existing column comments (COMMENT ON COLUMN) enhance output quality significantly
• Knowledge of the business domain for meaningful table/column descriptions

Instructions

1. Extract the complete table inventory: SELECT table_name, obj_description((table_schema || '.' || table_name)::regclass) AS table_comment FROM information_schema.tables WHERE table_schema = 'public' AND table_type = 'BASE TABLE' ORDER BY table_name (PostgreSQL). For MySQL: SELECT TABLE_NAME, TABLE_COMMENT FROM information_schema.TABLES WHERE TABLE_SCHEMA = DATABASE().

2. For each table, extract column details: SELECT c.column_name, c.data_type, c.character_maximum_length, c.is_nullable, c.column_default, pgd.description AS column_comment FROM information_schema.columns c LEFT JOIN pg_catalog.pg_description pgd ON pgd.objsubid = c.ordinal_position AND pgd.objoid = (c.table_schema || '.' || c.table_name)::regclass WHERE c.table_name = 'target_table' ORDER BY c.ordinal_position.

3. Extract primary key and unique constraint definitions: SELECT tc.constraint_name, tc.constraint_type, kcu.column_name FROM information_schema.table_constraints tc JOIN information_schema.key_column_usage kcu ON tc.constraint_name = kcu.constraint_name WHERE tc.table_name = 'target_table' AND tc.constraint_type IN ('PRIMARY KEY', 'UNIQUE').

4. Extract foreign key relationships to build the relationship map: SELECT tc.table_name AS child_table, kcu.column_name AS child_column, ccu.table_name AS parent_table, ccu.column_name AS parent_column, rc.delete_rule, rc.update_rule FROM information_schema.table_constraints tc JOIN information_schema.key_column_usage kcu ON tc.constraint_name = kcu.constraint_name JOIN information_schema.referential_constraints rc ON tc.constraint_name = rc.constraint_name JOIN information_schema.constraint_column_usage ccu ON rc.unique_constraint_name = ccu.constraint_name WHERE tc.constraint_type = 'FOREIGN KEY'.