As noted with the configuration variable 4GL_MAX_DATE, invalid dates can be incorrectly written to the database. Invalid dates are written as NULL, but if the date is in the key, problems can occur. To avoid invalid date problems in this instance, use the 4GL_MIN_DATE configuration variable to set the low-value date.
The format is:
4GL_MIN_DATE = YYYYMMDD
The default date for 4GL_MIN_DATE is “19000101” (January 1, 1900).
See also: 4GL_MAX_DATE configuration file variable.