I have douwnloaded InterBase 4.0 for Linux from
http://www.interbase.com/download/linux/ and am amazed by its I18N
support. It doesn't have NATIONAL CHARACTER yet. It do support
CHRACTER SET syntax for CREATE DATABASE/CREATE TABLE/ALTER TABLE etc.,
however. Also, it has COLLATE syntax in WHERE/ORDER BY/GROUP BY. If
you were interested in how it does it, you could get PDF manulas from
same URL(Lang_Ref.pdf in IB_4.0_docs.tar.gz).
Talking about performance, InterBase is a little bit faster than
PostgreSQL 6.3.2 when using indexes, but is slower if no index exists.
--
Tatsuo Ishii
t-ishii(at)sra(dot)co(dot)jp