Database Skills Discovery

Provides automatic access to comprehensive database design, optimization, and implementation skills.

When This Skill Activates

This skill auto-activates when you’re working with:

• SQL databases (PostgreSQL, MySQL)
• NoSQL databases (MongoDB, Redis)
• Database schema design and modeling
• Query optimization and performance tuning
• Database migrations and schema evolution
• Connection pooling configuration
• ORM usage and patterns
• Database selection and architecture decisions

Available Skills

Quick Reference

The Database category contains 8 core skills:

1. postgres-schema-design – Schema design, relationships, data types, normalization
2. postgres-query-optimization – EXPLAIN plans, indexes, slow query debugging
3. postgres-migrations – Schema changes, zero-downtime, rollback strategies
4. mongodb-document-design – Document modeling, embedding vs referencing
5. redis-data-structures – Caching, sessions, rate limiting, leaderboards
6. database-connection-pooling – Pool configuration, debugging exhaustion
7. orm-patterns – ORM best practices, N+1 prevention, eager loading
8. database-selection – Choosing databases, SQL vs NoSQL decisions

Load Full Category Details

For complete descriptions and workflows:

Read /skills/database/INDEX.md

This loads the full Database category index with:

• Detailed skill descriptions
• Usage triggers for each skill
• Common workflow combinations
• Cross-references to related skills

Load Specific Skills

Load individual skills as needed:

PostgreSQL skills

Read /skills/database/postgres-schema-design.md Read /skills/database/postgres-query-optimization.md Read /skills/database/postgres-migrations.md

NoSQL skills

Read /skills/database/mongodb-document-design.md Read /skills/database/redis-data-structures.md

Cross-database skills

Read /skills/database/database-connection-pooling.md Read /skills/database/orm-patterns.md Read /skills/database/database-selection.md

Common Workflows

New Database Project

Sequence: Selection → Schema design → Connection pooling

Read /skills/database/database-selection.md # Choose database Read /skills/database/postgres-schema-design.md # or mongodb-document-design.md Read /skills/database/database-connection-pooling.md

Query Performance Debugging

Sequence: Optimization → Connection pooling → ORM patterns

Read /skills/database/postgres-query-optimization.md # Debug slow queries Read /skills/database/database-connection-pooling.md # Check pool settings Read /skills/database/orm-patterns.md # Fix N+1 queries

Schema Evolution

Sequence: Schema design → Migrations

Read /skills/database/postgres-schema-design.md # Design changes Read /skills/database/postgres-migrations.md # Implement safely

Caching Layer

Sequence: Redis structures → Cache patterns

Read /skills/database/redis-data-structures.md # Redis patterns Then load caching skills via discover-caching gateway

Skill Selection Guide

PostgreSQL skills (relational, ACID, complex queries):

• postgres-schema-design.md – Design relational schemas
• postgres-query-optimization.md – Optimize complex queries
• postgres-migrations.md – Evolve schema over time

MongoDB skills (document-oriented, flexible schema):

• mongodb-document-design.md – Design document structures
• Choose when: Flexible schema, nested data, rapid iteration

Redis skills (in-memory, key-value, caching):

• redis-data-structures.md – Caching, sessions, rate limiting
• Choose when: Speed critical, caching layer, real-time features

Cross-database skills:

• database-selection.md – Start here for new projects
• database-connection-pooling.md – All databases need this
• orm-patterns.md – When using ORMs (SQLAlchemy, Prisma, Mongoose)

Integration with Other Skills

Database skills commonly combine with:

API skills (discover-api):

• API endpoints → Database queries
• Connection pooling for API servers
• Query optimization for API performance
• Migrations alongside API versioning

Backend language skills (discover-backend):

• Python: SQLAlchemy, psycopg2, PyMongo
• Zig: PostgreSQL C bindings
• Rust: SQLx, Diesel
• Go: database/sql, GORM

Testing skills (discover-testing):

• Integration tests with test databases
• Migration testing
• Query performance testing
• Data fixture management

Data pipeline skills (discover-data):

• ETL from databases
• Database as data source
• Bulk data operations
• Streaming database changes (CDC)

Observability skills (discover-observability):

• Query metrics and slow query logs
• Connection pool metrics
• Database performance monitoring
• Alert configuration

Progressive Loading

This gateway skill (~200 lines, ~2K tokens) enables progressive loading:

• Level 1: Gateway loads automatically (you’re here now)
• Level 2: Load category INDEX.md (~3K tokens) for full overview
• Level 3: Load specific skills (~2-4K tokens each) as needed

Total context: 2K + 3K + skill(s) = 5-10K tokens vs 25K+ for entire index.

Quick Start Examples

“Design a PostgreSQL schema for an e-commerce app”: Read /skills/database/postgres-schema-design.md

“Why is my query slow?”: Read /skills/database/postgres-query-optimization.md

“How do I safely change my database schema?”: Read /skills/database/postgres-migrations.md

“Should I use MongoDB or PostgreSQL?”: Read /skills/database/database-selection.md

“Implement caching with Redis”: Read /skills/database/redis-data-structures.md

“Fix N+1 queries in my ORM”: Read /skills/database/orm-patterns.md

Database Type Decision Tree

Need ACID transactions? YES → PostgreSQL
Need complex queries/joins? YES → PostgreSQL
Need flexible schema? YES → MongoDB
Need real-time caching? YES → Redis
Need full-text search? YES → PostgreSQL (with extensions) or Elasticsearch
Need graph relationships? YES → Neo4j or PostgreSQL (with extensions)
Need analytics? YES → DuckDB or Redpanda + Iceberg

For detailed decision-making: Read /skills/database/database-selection.md

PostgreSQL Focus Areas

Schema design → postgres-schema-design.md:

• Tables, columns, data types
• Primary keys, foreign keys, constraints
• Normalization vs denormalization
• Indexing strategies

Query optimization → postgres-query-optimization.md:

• EXPLAIN and EXPLAIN ANALYZE
• Index selection and creation
• Query plan analysis
• Performance tuning

Migrations → postgres-migrations.md:

• Schema change strategies
• Zero-downtime deployments
• Rollback procedures
• Migration tools (Alembic, Flyway, migrate)

NoSQL Focus Areas

MongoDB → mongodb-document-design.md:

• Document structure and embedding
• References vs embedding tradeoffs
• Schema versioning
• Index design for documents

Redis → redis-data-structures.md:

• Strings, hashes, lists, sets, sorted sets
• Caching patterns and TTLs
• Session storage
• Rate limiting implementations
• Leaderboards and counters

ORM Considerations

Before using ORMs, load: Read /skills/database/orm-patterns.md

Common ORM pitfalls:

• N+1 query problems
• Lazy vs eager loading confusion
• Transaction management
• Raw SQL when necessary
• Migration generation

Supported ORMs:

• SQLAlchemy (Python)
• Prisma (TypeScript/Node.js)
• Diesel (Rust)
• GORM (Go)
• ActiveRecord (Ruby)
• Entity Framework (C#)

Usage Instructions

1. Auto-activation: This skill loads automatically when Claude Code detects database work
2. Browse skills: Run Read <cc-polymath-root>/skills/database/INDEX.md for full category overview
3. Load specific skills: Use bash commands above to load individual skills
4. Follow workflows: Use recommended sequences for common patterns
5. Decision support: Start with database-selection.md for new projects

Next Steps: Run Read <cc-polymath-root>/skills/database/INDEX.md to see full category details, or load specific skills using the bash commands above.