Subject Re: [firebird-support] Re: TIME calculation errors
Author Helen Borrie
At 12:25 PM 18/04/2005 +0000, you wrote:


> > Yup. Linguistic confusion. TIME answers the question "what is the
>time?",
> > not "what time did it take?"
> >
>Helen,
>excuse me if i wrong, but,
>we can use TIME data type to store elapsed time if we have good enough
>reasons.

No. You can't. What would you store if the elapsed time exceeded one day?

>if both time values in same day, we can use delta value to reset
>start_time, to use as chronometer.
>TIME allways gives an elapsed value if u ask "what is the time?"
>because there is no date info in it.

It's true that it *represents* an elapsed value in storage, insofar as it
is "the time elapsed since midnight today". We just don't know/care what
day. It will roll over to 00:00:00.0000 as soon as it has passed
23:59:59.9999.

>so "what is the time?" is actually mean of "what time did it take?"
>from midnight.

In the same fashion as "what is the date?" means "How long has it been
since AD 0.0.0000?" But dates (like times) are interpreted as
snapshots. When we subtract one from another, we get an interval of time -
"How much time elapsed between these two moments?"

./hb