mongodb-schema-design

# MongoDB Schema Design Data modeling patterns and anti-patterns for MongoDB, maintained by MongoDB. Bad schema is the root cause of most MongoDB performance and cost issues—queries and indexes cannot fix a fundamentally wrong model. ## When to Apply Reference these guidelines when: - Designing a new MongoDB schema from scratch - Migrating from SQL/relational databases to MongoDB - Reviewing existing data models for performance issues - Troubleshooting slow queries or growing document sizes - Deciding between embedding and referencing - Modeling relationships (one-to-one, one-to-many, many-to-many) - Implementing tree/hierarchical structures - Seeing Atlas Schema Suggestions or Performance Advisor warnings - Hitting the 16MB document limit - Adding schema validation to existing collections ## Quick Reference ### 1. Schema Anti-Patterns - 3 rules - [antipattern-unnecessary-collections](references/antipattern-unnecessary-collections.md) - Splitting homogeneous data into multiple collections is often an anti-pattern; consult this reference to validate whether this is the case. - [antipattern-excessive-lookups](references/antipattern-excessive-lookups.md) - When encountering overly normalized collections that reference each other or frequent and possibly slow $lookup operations, consult this reference to validate whether this is problematic and how to fix it. - [antipattern-unnecessary-indexes](references/antipattern-unnecessary-indexes.md) - Consult this reference when ind...