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For example, if you are in Texas and you need to take a flight to the East coast, the airport marquis will display the takeoff time and landing time in your local time. I am trying to get the DB to display dates in the same way it works at airports. That is, at the same moment described above SYSDATE changed from ' 01:59:59' to ' 03:00:00' however with no indication of a time zone offset change.
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Note, the same change is visible in SYSDATE values, except that they have no time zone and no fractional seconds. The same effect would be seen on a correctly configured Unix-like system (based on the TZ variable or other OS-specific time zone mechanism). (This change was equivalent to a change in UTC from ' 09:59:59.999999 00:00' to ' 10:00:00.000000 00:00', that is, as expected, the system UTC time changed only by the expected fraction of the second, as determined by the clock resolution.)
ORACLE DATABASE TIMEZONE WINDOWS
For example, if the database is on Windows and the Windows system time zone is "Pacific Time (US & Canada)", then at the last DST change in March the SYSTIMESTAMP value changed from ' 01:59:59.999999 -08:00' to ' 03:00:00.000000 -07:00'. The timezone offset associated with this system timestamp changes to show the new offset of the local time from UTC. That is, if the operating system clock, as seen by OS sessions that spawn DB processes, switches the local time on DST boundary, then SYSTIMESTAMP also shows the new OS local time. You need proper OS configuration for DST change to be seen in the SYSTIMESTAMP value. System timestamp and the time zone offset it includes is based on OS time and is independent of the DB timezone file. This file is used by the database when time zone regions are converted to offsets before datetime calculations or when TZH:TZM format is used to display a region time zone from a datetime value.
ORACLE DATABASE TIMEZONE UPDATE
It was needed to update information about starting and ending times for DST to match the most current legislation.
ORACLE DATABASE TIMEZONE PATCH
The patch you mention was, most probably, an update to the database timezone file. I hoped that EXTRACT(TIMEZONE_REGION) automatically returns an offset-formatted string, like "-07:00" for PST, when the region is unknown, but this is clearly not the case. SELECT EXTRACT(TIMEZONE_HOUR FROM SYSTIMESTAMP)||':'|| EXTRACT(TIMEZONE_MINUTE FROM SYSTIMESTAMP)FROM dual If SELECT (EXTRACT(TIMEZONE_REGION FROM SYSTIMESTAMP)) FROM dual returns UNKNOWN, then you need: I recommend leaving DB time zone at offset '00:00' so that TIMESTAMP WITH LOCAL TIME ZONE may be used to store UTC-normalized time values. If it was set to a region name, DBTIMEZONE returns the region name.
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If it was set to an offset, DBTIMEZONE returns the offset. The database time zone is determined at database creation time and it defaults to '00:00'. You have to retrieve the time zone region name directly from the operating system using one of the available database interfaces to the outside world (Java, external C callouts, a local web service started on your host and accessed via UTL_HTTP, etc.) When daylight saving time gets into effect in the operating system, the offset changes automatically. The calculated difference is the system time zone in offset form. Oracle Database determines the system time zone by subtracting UTC time from local time, both retrieved from the operating system. Oracle Database does not know the region name of the system time zone. Do you mean the system time zone (EXTRACT(TIMEZONE_REGION FROM SYSTIMESTAMP)) or the database time zone (DBTIMEZONE)? These are different values used for different purposes.