""Carsten Schäfer"" <ca_schaefer@...> schrieb im Newsbeitrag news:<000c01c4d2ce$f4e857e0$0b00a8c0@zander>...

>
> Hi,
> I'm using Firebird 1.5.2 RC3.
> I have 2 tables (definitions at the end of this message):

Those table definitions are quite confusing. A first step in understanding would be to name the indices/constraints. This way, you can see which indices the query plan optimizer uses. The table layout looks like you could normalize the whole thing, to make queries faster.

There are some comparators which cannot be used with indices. I would suggest you try
http://ems-hitech.com/ibmanager
(No, I dont work for them, it's simply a great database manager) There is a trial available, and when executing queries, it not only shows the adapted query plan, but also time needed and a report about indexed/non-indexed reads on each table necessary to create the result set. Sometimes ist sufficient to create both an ASC and a DESC index on the table column, to make the query fast.

Another pointer would be the language reference at:
http://www.ibphoenix.com/downloads/60All.zip

Have fun, Alex