[Zope] Sybase: How generate id keys? (surrogate keys)

[Hung Jung Lu]

bill anderson <bil-@libc.org> wrote:
>IOW, would a random, unique id work for you?

Yes, it'll be fine.

>http://www.zope.org/Members/Bill/Documentation/AutoGenID

Thanks. That is the current work-around that I am using...
(Key derived from a time-stamp with millisecond precision.)
There is one observation and two problems:

(1) ZopeTime is not as good as the getdate() function
    from Sybase, if you are running multiple Zope
    webservers (for load-balancing.) That is, it's
    better to rely on one unique source of timer.

(2) There is a slight chance of two processes getting
    the same key, if they happen to occur within one
    millisecond of each other. The probability is small,
    but unfortunately I have to address even this minuscule
    probability. :(

(3) If the server's time is re-adjusted for any reason,
    it's possible that some keys are regenerated.

I agree that the millisecond-precision key is really good
for non-critical applications. But because of the nature of
our project, we need to address even the slightest chance
of error. :(

I think I will adapt the Sybase's recommended stored procedure
to Zope, by using DTML and ZSQL methods. It's kind of nasty
for something as simple as a surrogate key generation, but it
seems more secure.

thanks again,

Hung Jung

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com