참고자료
- BSON 스펙: https://bsonspec.org/spec.html
- MongoDB의 Shared 클러스터 공식 문서: https://www.mongodb.com/docs/manual/core/sharded-cluster-components/
- Mongoose 공식문서: https://mongoosejs.com/
- MongoDB의 Node.js Native Driver: https://www.mongodb.com/docs/drivers/node/current/
- Foreign Key: https://www.postgresql.org/docs/current/ddl-constraints.html#DDL-CONSTRAINTS-PRIMARY-KEYS