Re: YEAR 2000 Problem with existing Databases

REPLY TO: clb_at_shore.net

George:

     For beginners: Let's say you have a database that is responsible for month to month or year to year aggregations. Assume, the aggregations are based on a two digit year and allows the database to use the default century. Now, when we change to the year 2000 how will the database interpret this code, i.e. 99. Will it interpret as 1999 or as 2099? Also, when 00 is used, will the database know that the aggregated date is 2000 and not 1900?

    One way around the above coding problem is to always require the century and year in the code, i.e. a 4 digit format of : CCYY, such as 1999 or 2000. However, even if this format could be agreed upon, it is not always strictly enforced. And, it is too late to require all applications to have a four digit format for backward compatibility.

    So Oracle did the next best thing, and it makes its own default assumptions in preparing for the year 2000. When the database sees '00', it will assume that it is the year 2000 not 1900. How to get around this default, if you want it to actually be 1900 you might ask? The answer is simple: code it as a four digit format, i.e. '1900'.

    How does Oracle know that '00' is the 21st. century, 2000 and not 1900? Well, they use an algorithm that signifies the default century of 2000 recognized in their code as 'R'. If you look in one of the later Language Manuals under the date formats, you will find a section explaining the 'R' logic and Oracle's handling of the year 2000 for dates.

    In any event, this should provide a lot of conversion work for all the old applications out there, that need to signify the year 2000, as quite a few are coded as '00' or '99' and when automatically updated to '00' will have to be defaulted to the century 2000, not 1900.

    Hope this helps.

clb.
"A man's character is his fate."

                        Heraclitus.

In article <4b4n22$o41_at_aldebaran.sct.fr>, <georgeb_at_worldnet.net> writes:
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> From: Bruno GEORGES <georgeb_at_worldnet.net>
> Newsgroups: comp.databases.theory,comp.databases.oracle
> Subject: YEAR 2000 Problem with existing Databases
> Date: 18 Dec 1995 21:39:14 GMT
> Organization: World-Net information exchange, Internet provider.
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> Xref: shore comp.databases.theory:5990 comp.databases.oracle:54271
>
> Hi dear readers,
>
> I just started working in IT and will be in charge very soon
> for resolving the famous "YEAR 2000" problem.
>
> My request is:
>
> Is there anybody who knows what are the main problems generated by
> this issue, and what are the actions to consider in an Information
> System.
>
> Thank you so far, I'll really appreciate any answer
>
> /********************************************************
> Bruno Georges
> MSc Computer Science
> 5, rue Pierre Louys
> 75016 Paris
> *********************************************************/
>
>
Received on Wed Dec 27 1995 - 00:00:00 CET