On 17 May 2021 13:27:40 -0000 hamann.w@xxxxxxxxxxx wrote: > in unicode letter ä exists in two versions - linux and windows use a > composite whereas macos prefers the decomposed form. Is there any way > to make a semi-exact match that accepts both variants? You should probably normalise the strings in whatever application code handles the inserting. NFC is the "usually sensible" normal form to use. If you can't change the application code, you may use a trigger and apply the `normalize(text[,form])→text` function to the values https://www.postgresql.org/docs/13/functions-string.html#id-1.5.8.10.5.2.2.7.1.1.2 something vaguely like (totally untested!):: create function normalize_filename() returns trigger as $$ begin new.filename := normalize(new.filename); return new; end; $$ language plpgsql; create trigger normalize_filename before insert or update on that_table for each row execute function normalize_filename(); -- Dakkar - <Mobilis in mobile> GPG public key fingerprint = A071 E618 DD2C 5901 9574 6FE2 40EA 9883 7519 3F88 key id = 0x75193F88
