Re: use of DBCENTURY

On Tue, 14 Jul 1998, Infodata wrote: > I would appreciate some insight into the use of DBCENTURY variable. RTM? > Do both the tool and the server require to support DBCENTURY, to use its > features, or is it sufficient for the server to only have this capability? It depends on how much you like nasty surprises. * If you don't mind them, then you can use a mixed-capability combination. * If you don't like them, then you should use a matched set of tools and engines. They should either both be aware of DBCENTURY or, possibly, both unware of it. It is recommended that you upgrade to DBCENTURY-aware software. If you don't, make sure you always display all 4 digits of the year in every date that is displayed. If you don't (won't) do that, expect problems. The problems occur when a date is translated from a string into a DATE value and the string only has 2-digits for the year. If your application doesn't handle DBCENTURY, it will always add 1900 when it does the conversion; if the database handles DBCENTURY, it might add 1800, 1900, 2000 or even 2100, depending on DBCENTURY and the current date. Or the reverse could be true if the database is not aware of DBCENTURY but the application is. Consequently, you might get different answers when the engine does the conversion and when the tool does the conversion. If the tool is I4GL, most of the date conversions will be done in the front-end code and it would be silly not to upgrade to a DBCENTURY-aware version of the software, unless you are sure that all your dates are displayed with 4 digits for the year and your users are used to typing all 4 digits when they enter the year -- and that is improbable! They will probably just type 2 digits for the year and it automatically gets converted from 98 to 1998; the snag is, when they type 00, it will be automatically converted to 1900 once the century rolls over. The documentation says that 1900 is added, and it means 1900 is added. > What are the values that can be assigned to this environment variable? According to TFM: C, P, F, R > I understand that it can be used to change the default century to the > century closest, before or after the current date. But what are the > respective settings for these? C, P, F Yours, Jonathan Leffler (jleffler@informix.com) #include <witticism.h> Guardian of DBD::Informix -- see http://www.perl.com/CPAN