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typvtypv/nest-turbo-starter/.claude/skills/databases/SKILL.md

databases

Skill224 starsChanged 3 months agoMITView on GitHub

Design schemas, write queries for MongoDB and PostgreSQL. Use for database design, SQL/NoSQL queries, aggregation pipelines, indexes, migrations, replication, performance optimization, psql CLI.

We split this skill into the rules it gives an agent

5 rules. 5 are common, 0 are distinctive, and 0 are very specific to this project.

  • 5

    Common

    Most of the 17 edited versions we read keep these.

  • 0

    Distinctive

    This author's own choices. Worth a look.

  • 0

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Common:

    Use embedded documents for 1-to-few relationships

    line 64
  2. Common:

    Use aggregation pipeline for complex transformations

    line 67
  3. Common:

    Use Atlas for managed hosting

    line 69
  4. Common:

    Use foreign keys for referential integrity

    line 73
  5. Common:

    Use EXPLAIN ANALYZE to optimize queries

    line 75

“Common” is measured: kept by at least 6 in 10 of the 17 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Databases Skill

Unified guide for working with MongoDB (document-oriented) and PostgreSQL (relational) databases. Choose the right database for your use case and master both systems.

When to Use This Skill

Use when:

  • Designing database schemas and data models
  • Writing queries (SQL or MongoDB query language)
  • Building aggregation pipelines or complex joins
  • Optimizing indexes and query performance
  • Implementing database migrations
  • Setting up replication, sharding, or clustering
  • Configuring backups and disaster recovery
  • Managing database users and permissions
  • Analyzing slow queries and performance issues
  • Administering production database deployments

Reference Navigation

Database Design

  • db-design.md - Activate when user requests: Database/table design for transactional (OLTP), analytics (OLAP), create or extend schema, design fact/dimension tables, analyze/review CSV/JSON/SQL files to create tables, or need advice on data storage structure.

MongoDB References

  • mongodb-crud.md - CRUD operations, query operators, atomic updates
  • mongodb-aggregation.md - Aggregation pipeline, stages, operators, patterns
  • mongodb-indexing.md - Index types, compound indexes, performance optimization
  • mongodb-atlas.md - Atlas cloud setup, clusters, monitoring, search

PostgreSQL References

  • postgresql-queries.md - SELECT, JOINs, subqueries, CTEs, window functions
  • postgresql-psql-cli.md - psql commands, meta-commands, scripting
  • postgresql-performance.md - EXPLAIN, query optimization, vacuum, indexes
  • postgresql-administration.md - User management, backups, replication, maintenance

Python Utilities

Database utility scripts in scripts/:

  • db_migrate.py - Generate and apply migrations for both databases (MongoDB and PostgreSQL)
  • db_backup.py - Backup and restore MongoDB and PostgreSQL
  • db_performance_check.py - Analyze slow queries and recommend indexes
# Generate migration
python scripts/db_migrate.py --db mongodb --generate "add_user_index"

# Run backup
python scripts/db_backup.py --db postgres --output /backups/

# Check performance
python scripts/db_performance_check.py --db mongodb --threshold 100ms

Best Practices

MongoDB:

  • Use embedded documents for 1-to-few relationships
  • Reference documents for 1-to-many or many-to-many
  • Index frequently queried fields
  • Use aggregation pipeline for complex transformations
  • Enable authentication and TLS in production
  • Use Atlas for managed hosting

PostgreSQL:

  • Normalize schema to 3NF, denormalize for performance
  • Use foreign keys for referential integrity
  • Index foreign keys and frequently filtered columns
  • Use EXPLAIN ANALYZE to optimize queries
  • Regular VACUUM and ANALYZE maintenance
  • Connection pooling (pgBouncer) for web apps

Resources

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