The datetime data types include DATE, TIME, and TIMESTAMP. Although datetime values can be used in certain arithmetic and string operations, and are compatible with certain strings, they are neither strings nor numbers.
Date
A date is a three-part value (year, month, and day). The range of the year part is 0001 to 9999. The range of the month part is 1 to 12. The range of the day part is 1 to x, where x depends on the month.
The internal representation of a date is a string of 4 bytes. Each byte consists of 2 packed decimal digits. The first 2 bytes represent the year, the third byte the month, and the last byte the day.
The length of a DATE column, as described in the SQLDA, is 10 bytes, which is the appropriate length for a character string representation of the value.
Time
A time is a three-part value (hour, minute, and second) designating a time of day under a 24-hour clock. The range of the hour part is 0 to 24. The range of the other parts is 0 to 59. If the hour is 24, the minute and second specifications are zero.
The internal representation of a time is a string of 3 bytes. Each byte consists of 2 packed decimal digits. The first byte represents the hour, the second byte the minute, and the last byte the second.
The length of a TIME column, as described in the SQLDA, is 8 bytes, which is the appropriate length for a character string representation of the value.
Timestamp
A timestamp is a seven-part value (year, month, day, hour, minute, second, and microsecond) designating a date and time as defined above, except that the time includes a fractional specification of microseconds.
The internal representation of a timestamp is a string of 10 bytes. Each byte consists of 2 packed decimal digits. The first 4 bytes represent the date, the next 3 bytes the time, and the last 3 bytes the microseconds.
The length of a TIMESTAMP column, as described in the SQLDA, is 26 bytes, which is the appropriate length for the character string representation of the value.