- Date: A calendar date.
- Time: A clock time, optionally with a UTC offset.
- Datetime: A calendar date together with a clock time, optionally with a UTC offset.
Note: For convenience, Datetime is often used as a synonym of temporal value.
Interval: A period of time between two temporal values. Example: Date + interval.
- Duration: Same as interval. Example: Duration of a project.
- Period: Same as interval. Example: Period of time.
- Difference: Same as interval. Example: Difference between dates.
The standard FME format for date, time, and datetime values is:
- Date: yyyymmdd
- Time: hhmmss or hhmmss.123456789
- Time with offset: [Time][UTC offset]
- Datetime: [Date][Time]
- Datetime with offset: [Datetime][UTC offset]
- Any date/time value in the above syntax, and which corresponds to a real point in time, is considered valid.
- Invalid date/time values include:
- Partial dates (for example, year-month) or times (for example, hours-minutes).
- Date/time values that exceed supported ranges.
- Dates that do not exist in the Proleptic Gregorian calendar.
- Malformed UTC offsets.
- Empty or null date/time values.
Example: 111730, 111730.135
|yyyy||4-digit year, with range 0001 to 9999||2011|
|dd||2-digit day of month||05|
|hh||2-digit hour of a 24-hour clock||14|
Optional fraction of a second, up to 9 digits or nanosecond resolution. Additional fractional digits are accepted, but only 9 fractional digits are kept during temporal arithmetic. Trailing zeros in the fractional digits are automatically trimmed.
Only the "
Time zone offset with syntax [+|-]hh:mm (default), [+|-]hhmm, or [+|-]hh.
Note: It is a common mistake to misinterpret how UTC offsets are applied. For example, 8PM-08:00 (Pacific Standard Time) is equivalent to 11PM-05:00 (Eastern Standard Time). To get the UTC times, add the negated UTC offset to the unzoned times: 8PM+08:00 = 4AM the next day, and 11PM+05:00 = 4AM the next day. Therefore, @DateTimeDiff(200000-08:00,230000-05:00) = PT0S, meaning the two times are identical in terms of UTC time.
The FME interval format is based on the ISO 8601 duration format:
- Example: -P1Y2M3DT4H5M6.123456789S
- The "-" sign indicates a negative interval.
- P is a delimiter character meaning "Period".
- Y = year, M = month, D = day, T = delimiter disambiguating month and minutes, H = hours, M = minutes, and S = seconds.
- Only the seconds field is a floating point value. The other fields are integers.
- The delimiters P, Y, M, D, T, H, M, and S must occur in that order. So, P1M1Y is invalid.
- If a field has the value 0, it is omitted. If all fields have value 0, PT0S is returned.
- All fields must be positive, unless all fields are zero. The "-" sign specifies a negative interval.