Comment by evanelias

Flyway is primarily an imperative migration tool, rather than a declarative-first system. Their paid editions do have support for doing diffs ("state-based") and auto-generating migrations, but it's bolted-on to a workflow that was designed to be imperative-first. From what I can find, their public docs are rather lacking on what types of database objects and edge cases it supports.

Skeema does indeed separate each DB object to its own file, and each logical schema to its own subdirectory. It also figures out how to correctly apply changes in a valid order, but yeah it's MySQL/MariaDB only. I think some of the declarative FOSS Postgres tools do attempt to provide a correct ordering, but from memory I'm not certain.