Remedy DST Time addition problems
When the DST match doesn’t appear to add up:
Here’s the original ARS List post I put out:
Fortunately this issue SHOULD be very straight forward.
Unfortunately – it isn’t.
There’s a button that calculates a person’s period of eligibility to make changes to their HR benefits, etc. You enter their employment anniversary date and hit the button and this performs a calculation:
$My Date$ – 864000 (i.e., minus 10 days).
Here’s the interesting thing – when the date entered is Daylight savings time – 3/15 this spring – the calculated value for the date time field returns 3/4/2010 11:00:00 PM. Normally all of the times in this date/time field are left at 12:00:00 AM and are unused.
Technically speaking the calculation is EXACTLY correct. 3/4/2010 11:00:00 PM is exactly 10 days before 3/15/2010 12:00:00 AM – because 3/15 has an “extra” hour added that is a figment of our collective imagination. Technically DST doesn’t happen until 2:00 AM though but that’s a matter for another time.
I was thinking about changing the times on these to default to 3:00:00 AM instead of 12:00:00 AM – but I’m open to suggestions.
As it turns out the solution was really simple – the original math for the “Set Fields” calculation did this:
$My Date$ – 864000
I just switched it to use the Remedy DATEADD function and added negative 10 days – this only evaluates the “date” portion of the value and ignores DST:
Thanks to C.B. on the arlist for the suggestion.