> On Mar 6, 2015, at 9:58 AM, brian brian@... [firebird-support] <firebird-support@yahoogroups.com> wrote:
>
> My problem is that I must avoid duplicated records in the database,
> the unique key is a complicated structure containing four 16-bit words
> plus a 108-bit set of flags. The combination of the whole lot must be
> unique. I don't need to retrieve this data other than to check for
> duplicate records, so I can massage it in FreePascal so that it can go
> into the database in any form that's desirable.

If there's any chance that you'll ever need data fromt the four 16-bit words, I'd create a five part primary key with four small integers followed by a 14 byte string octets. Firebird index keys are compressed and rearranged so they compare bytewise regardless of the original format - single field or multiple, combinations of strings and numbers, etc. If it were me, I'd let Firebird create the key from data.

>
>
> If I were using PostgreSQL, I'd store the whole lot as a single
> 172-bit bitstring, but I can't find any mention of an equivalent data
> type in the Firebird documentation that I've been able to find.

String of type octets works.

>

Good luck,

Ann