# Advanced Usage While the functions provided by the library cover lots of use cases, there are other times where applications need something else. Below are some of those. - [Customizing Serialization][ser] - [Related Documents and Custom Queries][rel] - [Referential Integrity][ref] (PostgreSQL only)
This page is an appendix to the conceptual part of "Relational Documents". Its example documents use PascalCase instead of camelCase, but the concept is the same. [ser]: ./custom-serialization.md "Advanced Usage: Custom Serialization • PDODocument • Relational Documents" [rel]: ./related.md "Advanced Usage: Related Documents • PDODocument • Bit Badger Solutions" [ref]: /concepts/referential-integrity.html "Appendix: Referential Integrity with Documents • Concepts • Relational Documents"