At 10:03 PM 5/05/2009, you wrote:

>Hi,
>
>We want to store 64 bit integers in a FB 2.1 database (2.5 as soon as
>it's out and tested with our ECO app).
>
>What datatype should we use?

BigInt, alias NUMERIC (18,0)

>Also, does FB have a special GUID datatype? (I suppose char would do,
>but it's really just a very large integer isn't it? 128 bit?)

char or varchar of character set OCTETS of the desired length and store your values in hex format. There's no need for it to be of a number type, since you never do arithmetic on a GUID, only equivalence/distinct comparisons. If you plan to use lots of them, create a domain.

./hb