The Validate command aims to ensure that Flyway can reliably reproduce an existing version of a database from the source migration scripts by warning you if files are retrospectively added, removed or altered that would prevent it from doing so. Validation errors are Flyway's warning that "the source for this version has changed". Read more
The Clean command resets a database to its initial state, before any Flyway migrations were applied. In other words, it empties the database. This can be useful for any development task that requires that you recreate the database structure, or for tearing down a test harness. It also allows you to try out experiments and alternative strategies within an isolated feature branch, and then reverse out of them. Read more