Determination of the implicit time zone

Db2 uses the IMPLICIT_TIMEZONE parameter of DSNHDECP to implicitly determines the time zone to associate with a value that does not have a time zone on assignment to a TIMESTAMP WITH TIME ZONE column or variable.

The IMPLICIT_TIMEZONE parameter of DSNHDECP is used to support operations that combine TIMESTAMP WITHOUT TIME ZONE values and TIMESTAMP WITH TIME ZONE values and indicates the time zone to associate with TIMESTAMP WITHOUT TIME ZONE values. For example, on assignment of a value that does not have time zone information (the TIMESTAMP WITHOUT TIME ZONE data type, or a string representation of a timestamp without a time zone) to a TIMESTAMP WITH TIME ZONE target such as a column or variable, Db2 implicitly determines the time zone to associate with the value. The implicit time zone is determined as follows:

• If IMPLICIT_TIMEZONE is not specified or is specified as CURRENT, the implicit time zone is the value of the CURRENT TIME ZONE special register.
• If IMPLICIT_TIMEZONE is specified as SESSION, the implicit time zone is the value of the SESSION TIME ZONE special register.
• If IMPLICIT_TIMEZONE is specified as a character string in the format of '±th:tm' , the implicit time zone is the time zone value represented by the character string.