Which characters can be used for user password in Firebird?
The only limitation for Firebird password is length of maximum 8 characters. Those can be any characters, i.e. any sequence of bytes (0-255), zero might be hard to insert. You should check your connectivity library (access method) for what is supports, since some tools allow you to put some characters in password, but won't let you log in with that password later. If you decide to play with that, better use some non-SYSDBA account for testing, so that you can always reset the password. If you manage to damage SYSDBA password, read FAQ #55.