You can embed plantuml and drawio diagrams in Rust doc comments and have it rendered in the docs, using this crate
https://crates.io/crates/rsdoc
And you can generate plantuml from SQL tables using
https://crates.io/crates/sqlant (this one is a rust port of a go tool, https://github.com/achiku/planter)
And you can embed plantuml in mdbook
https://crates.io/crates/mdbook-plantuml