Hi,


I've to synchronies an X.500 (LDAP) Directory with some DB tables.
Keys in X.500 are DNs with more than 100 chars but with a very hi
difference in the first chars (there are the names, followed by
organisations).

I can't change the synchronization order from db to LDAP as there
are more targets for data than the db.

So I've build a trigger to copy 84 chars (longest varchar in
ISO8859_1) into another field on which I've put an index.

Problem: In Firebird until 1.5 I've found nothing to use this
index on my DN-Field in Database. Therefore every SELECT on an DN
causes about 40.000 unindexed reads and also the method


SELECT "Id" from USERS WHERE SUBSTRING(:LDAPDN from 1 for 84) =
USERS.SHORTDN AND :LDAPDN = USERS.DN

has the same result.

How can I get firebird to use my index? Subselect? Or do I 've to
cache al the data in perl hashes? :-(


regards

Björn