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ftTimeStampOffset

ftTimeStampOffset = 49

Example​

function HasTimestampOffset(Field: TField): Boolean;
begin
  Result := Field.DataType = ftTimeStampOffset;
end;

Usage​

ftTimeStampOffset identifies a structured SQL timestamp that retains separate timezone-hour and timezone-minute offset components.

Additional Technical Info​

ftTimeStampOffset is declaration ordinal 49 of TFieldType. Delphi maps it to TSQLTimeStampOffsetField. Its structured value extends the calendar/clock/millisecond components with signed TimeZoneHour and TimeZoneMinute fields.

Preserve the structured value or its custom Variant when the original offset matters. AsDateTime converts the represented instant into the current host's local civil time and discards the original offset components. The same stored row can therefore yield a different wall-clock TDateTime on hosts in different zones. Conversely, assigning a plain TDateTime attaches the host-local UTC offset for that date. A plain TDateTime has no zone flag, so this inference can be wrong for values intended as UTC or another locality.

Current Delphi paths use inconsistent minute-sign conventions for west-of-UTC fractional-hour offsets. Text parsing of -03:30 stores hour -3 and minute +30; formatting reproduces -03:30, but instant conversion combines those as -150 rather than -210 minutes. -00:30 loses its negative sign entirely. In the other direction, host-local offset inference obtains both negative hour and negative minute components from a negative TTimeSpan; the formatter passes that negative minute to EncodeTime, which can raise instead of formatting it. Avoid the affected text/AsDateTime round trips, retain and validate the structured/original value, and test the actual provider for any west-of-UTC fractional-hour zone.

Null is separate from the all-zero record. Fractional precision can be rounded by provider conversions. An offset identifies an instant but not a named timezone or its daylight-saving history; store a zone identifier separately when future civil-time rules matter.

The example only inspects metadata and was source-reviewed; no clock, timezone, timestamp conversion, dataset, database, runtime or image test ran.

External references

Created 2026-07-15