xs:duration
The xs:duration
type represents a length of time such as 15
minutes; 2 hours; or 3 years, 7 months, 2 days, 8 hours, 32
minutes, and 12 seconds. It does not have a specific beginning or
end, just a length. Durations are represented using the ISO-8601
standard format P
n Y
n M
n DT
n H
n M
n S.
n Y
gives the number of years, n M the number of months,
n D
the number of days, n H the number of hours,
n M
the number of minutes, and n S the number of seconds. The number of
years, months, days, hours, minutes, and seconds are all given as
nonnegative integers. The number of seconds is a decimal number
with as many places after the decimal point as necessary. For
example, in this format, 3 years, 7 months, 2 days, 8 hours, 32
minutes, and 12 seconds is written as P3Y7M2DT8H32M12S. Any values that are
zero can be omitted. Thus, a duration of 2 years and 2 minutes can
be written as P2YT2M. If there
are no hours, minutes, or seconds, then the T is omitted. Thus, a duration of two
years is written as P2Y. A
leading minus sign before the P
indicates a negative duration.
Constraining facets that apply to xs:duration are minInclusive, maxInclusive, minExclusive, maxExclusive, pattern, enumeration, and whiteSpace. However, because the number
of days in a month varies from 28 to 31 and the number of days in
a year varies from 365 to 366, durations are not always perfectly
ordered. For instance, whether P1M is greater than, equal to, or less
than P30D depends on which
month it is.