The century (QCENTURY) system value is used to specify the century. It is used with the system values QDATE and QYEAR to determine the specific date currently being used by the server.
The possible values are:
- 0 (the years from 1928 to 1999)
- 1 (the years from 2000 to 2053)
Note: 1900 to 1927 and 2054 to 2099 are not supported years for system time. Applications can, however, support year date ranges from 0001 to 9999.
You can set the value of QCENTURY with the century indicator, or the system sets the value of QCENTURY based on the following two situations:
- At the time of the first IPL, the system sets the initial value of QCENTURY based on the following rules:
- If QYEAR is equal to or greater than 40, the system assigns a value of 0 to QCENTURY.
- If QYEAR is less than 40, the system assigns a value of 1 to QCENTURY.
- When QYEAR or the year in QDATE is changed:
- QCENTURY is set to 0 if QYEAR is 54 to 99
- QCENTURY is set to 1 if QYEAR is 00 to 27
For example, if you change QYEAR from 95 to 13, the system changes QCENTURY from 0 to 1, indicating a year of 2013. However, if you change QYEAR from 95 to 45, the system will not change QCENTURY, because
both 1945 and 2045 are valid dates.
If you change this value, the change takes effect immediately. Changing this value also affects the system value QDATE.
Note: The 21st century begins at 0000 hours, 1 January 2001. However, for purposes of common understanding, the 20th/21st century boundary is defined to be between 2400 hours, 31 December 1999 and 0000
hours, 1 January 2000. This allows a discussion of the 21st century to include all dates with a 20xx format inclusive of the year 2000.