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Session Time Zone

As the name implies, the session time zone can be different for each database attachment.It can be set explicitly in the DPB with the item isc_dpb_session_time_zone;otherwise, by default, it uses the same time zone as the operating system of the Firebird server process.This default can be overridden in firebird.conf, setting DefaultTimeZone.

Note

Drivers may apply different defaults, for example specifying the client time zone as the default session time zone.Check your driver documentation for details.

Subsequently, the time zone can be changed to a given time zone using a SET TIME ZONE statement or reset to its original value with SET TIME ZONE LOCAL or ALTER SESSION RESET.

Time Zone Format

A time zone is specified as a string, either a time zone region (for example, 'America/Sao_Paulo') or a displacement from GMT in hours:minutes (for example, '-03:00').

A time/timestamp with time zone is considered equal to another time/timestamp with time zone if their conversions to UTC are equivalent.For example, time '10:00 -02:00' and time '09:00 -03:00' are equivalent, since both are the same as time '12:00 GMT'.

Important

The same equivalence applies in UNIQUE constraints and for sorting purposes.