#632 Year-check 1753-9999 not valid for type 'date'

[Simon Niederberger]

The constructor DateTime(Date d) runs packDate(), which then does a check on the date's year (valid: 1753-9999). However, this restriction only applies for 'datetime' and timestamp data types, but not for a 'date'. Sybase ASE allows years 0001 - 9999 for type 'date'.