17.10 - Usage Notes - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - Data Types and Literals

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1143-171K
Language
English (United States)

Storage

A PERIOD(TIMESTAMP[(n)]) is a variable length data type and is saved as two TIMESTAMP values. The ending bound value of UNTIL_CHANGED occupies a single byte for these variable length data types.

Element Type Field Size in bytes Maximum Size in bytes in the row
TIMESTAMP(n) 20 if ending bound is not UNTIL_CHANGED 24 if ending bound is not UNTIL_CHANGED
11 if the ending bound is UNTIL_CHANGED 16 if the ending bound is UNTIL_CHANGED

External Representation of PERIOD(TIMESTAMP)

In field mode, Vantage returns PERIOD(TIMESTAMP) data as character data.

Assume L is the maximum length of the formatted character string for the format associated with this Period data type. The resulting character string contains two strings representing the beginning and ending bounds of the period value expression, each up to length L , and each enclosed in apostrophes ('), separated by comma and a space (,), and then enclosed within a left and right parenthesis [( )]. Thus, the maximum length of the resulting character string is 2* L +8.

Assume the actual length is K which may be less than 2*L+8, for example, if the format includes the full names of months and the specific month for a bound is July.

For modes other than field mode, and for input data, the external representation of PERIOD(TIMESTAMP) consists of 2-bytes representing the length of the data followed by 2 consecutive timestamp values. Each timestamp value consists of multiple fields as explained below and returned in the specified order:
  • Second: 4-byte, signed integer flipped to client form. This integer represents the number of seconds as a scaled decimal (for example, 12.56 seconds is returned as 12560000).
  • Year: 2-byte, signed short integer flipped to client form. This integer represents the year value.
  • Month: 1 unsigned byte. This byte represents the month value.
  • Day: 1 unsigned byte. This byte represents the day of the month.
  • Hour: 1 unsigned byte. This byte represents the number of hours.
  • Minute: 1 unsigned byte. This byte represents the number of minutes.

Restrictions

A primary index column or partitioning column cannot be a column that has a Period data type.