[AccessD] Harkins and Brock

Hi Charlotte

Come on. Both you and Susan are clever people, this millisecond journey is just one of those areas where you may not know exactly what is going on because you either haven't had the need to know or really don't care. If you know what a double is, you are on your feet.

Susan's problem was that I had a hard time explaining what to use milliseconds for, and I could only find some generic uninspired examples. I haven't myself used the milliseconds for anything else than experiments, but thought it could be useful for some. But, as always, Susan found a twist to make the topic readable even for the not-so-enthusiastic reader.

The idea came one day where I wondered why SQL Server presents a time resolution of 3 ms while Access/VBA/JET only offers 1000 ms, both using the same underlying data type of double. So what was the resolution of double really? Much to my surprise, I found out that the resolution is 1 ms (or better) in the full range of data type date/time - from 100-1-1 00:00:00.000 to 9999-12-31 23.59.59.999. 

Then I created the functions needed to generate and read time values with milliseconds and to create a set of functions handling milliseconds that mimic the full range of the well-known date/time functions of Access/VBA. One of the challenges was to get the calculations with doubles right avoiding bit errors. This was solved by switching to data type decimal at some critical places.

/gustav


>>> cfoust at infostatsystems.com 12-09-2008 00:42 >>>
OK, all together now ...  "uh... huh????" :)

Is the jagged time thingie the reason why I run out of money before I
run out of time??

Charlotte Foust

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Susan Harkins
Sent: Thursday, September 11, 2008 3:12 PM
To: AccessD at databaseadvisors.com 
Subject: [AccessD] Harkins and Brock

http://www.devx.com/ 

I just wanted to share this article with you guys -- Gustav and I have
written a number of articles together but this one's different as I had
to ask him repeatedly... "uh... huh????" :)

I think it turned out really well and certainly will be useful to the
developers who actually need it.

Susan H.