This constant combines CURRENT DATE and CURRENT TIME to form a UTC TIMESTAMP value, which contains the year, month, day, hour,
minute, second, and fraction of a second as observed in GMT. The precision of the fraction is set to 3 decimal places. The
accuracy of this constant is limited by the accuracy of the system clock. See "CURRENT UTC TIMESTAMP special value" under
"Special values in UltraLite" in the SQL Anywhere documentation set.
The default value of existing tables can be determined by querying the system table TableSchema.SYS_COLUMNS's column_default