On Mon, Feb 20, 2006 at 07:24:05PM +0100, Karsten Hilbert wrote: > I am storing the maximum age a vaccination is due in a > patient (eg. "don't give this vaccination beyond the age of > 10 years" or some such). Some vaccinations are to be given > regardless of age. > > Up to now I have used NULL to mean "no maximum age". That > doesn't really feel right and also complicates the SQL > needed for retrieving data. > > I *could*, of course, use something like '999 years' as a > special value to indicate "no upper limit" figuring that no > one is going to live that long in the foreseeable future. > > However, the technically elegant and satisfying solution > would be to be able to use "infinite" with interval data > types much like "infinity" with timestamps. I have tried > various syntax attempts, calculations and casts but haven't > found any returning an interval of infinite length. The docs > and Google don't help, either. I suspect that you could create either a domain or a custom type that would handle this they way you wanted. -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
