Use the date and time types to hold dates, times
Firebird supports three different date/time
DATE stores a date as a 32-bit
longword. Valid dates are from January 1, 100 a.d. to February 29,
TIME stores time as a 32-bit longword. Valid
times are from 00:00 to 23:59.9999.
TIMESTAMP is stored as two 32-bit longwords
and is a combination of DATE and TIME.
Firebird always stores the full year value in a
DATE or TIMESTAMP column, never a two-digit abbreviated value. When a
client application enters a two-digit year value, Firebird uses the
“sliding window” algorithm to make an inference about the
two-digit year number entered to the current year modulo 100 If the
absolute difference is greater than 50, then infer that the century
of the number entered is 20, otherwise it is 19.
The below example declares a variable 'birthdate'
of type DATE:
DECLATE birthdate DATE;