Hi,
We use guids (or uuids) in our applications. For
firebird/interbase due to the prefix compression used in the index
keys you are better off reversing the byte order of the guid.

We wrote a guid udf library in C (available on the ibphoenix
website) for both windows and linux to generate the guids. It can
generate two forms of guid,

CREATE_GUID, 36 characters, normal "windows" guid with dashes.

and

CREATE_UUID, 22 characters, byte order reveresed for indexing. All
characters used are printable and can be used in urls. This is the
form we use in firebird.

There are also two functions to convert between the two.

We tried originally to return a 16 Byte number but had many
problems when one of the bytes was #0.

Regards
Ian Newby