The date part of a DATETIME has the following lower and upper limits: 1/1/32768 B.C. to 12/31/32767 A.D.
The time part has the following limits: 00:00:00.000 to 23:59:61.999.
The seconds can go beyond 60 to account for leap second adjustments (when the atomic clock gets out of sync with the earths revolution). ABL does not account for specific days that contain leap seconds when doing datetime arithmetic. For example, when subtracting two datetimes, the history of any days with leap seconds between those date times is lost—all days between are considered to have exactly 24*60*60*1000 milliseconds).
The time zone part of a DATETIME-TZ must be between -14:00 and +14:00.
