Vlad Mihalcea & Andrea Boriero: I've updated my PR to introduce a method Dialect.supportsIfExistsAfterAlterTable() *additionally * to the new Dialect.getAlterTableString() that now makes use of Dialect.supportsIfExistsAfterAlterTable() itself. That felt better on both user-side (because they are accustomed to override supportsIfXXX() in custom Dialects) and internally (because it doesn't create duplicated code for building up the strings).

I hope this is considered. Let me know if I can do something to help.

Cheers