TimeDateWZControl - Advanced SQL Engine

TimeDateWZControl - Advanced SQL Engine - Teradata Database

Database Utilities

Product

Advanced SQL Engine

Teradata Database

Release Number

17.00

Published

June 2020

Language

English (United States)

Last Update

2020-06-15

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B035-1102

lifecycle

Product Category

Teradata Vantage™

Purpose

Determines how TIME and TIMESTAMP data is stored in the Teradata Database file system. Also determines whether the built-in functions CURRENT_TIME, CURRENT_TIMESTAMP, and CURRENT_DATE reflect the session time and session time zone offset.

This field does not affect the output of the DATE and TIME built-in functions.

Field Group

General

Valid Settings

Setting	Description
0	Disabled. The values returned by the built-in time and date functions reflect the time value local to the Teradata Database server, but the time zone value that is defined for user or session. This is identical to a setting of 1.
1	Disabled. The values returned by the built-in time and date functions reflect the time value local to the Teradata Database server, but the time zone value that is defined for user or session. This is identical to a setting of 0.
2	Enabled. The values returned by the built-in time and date functions reflect the session time and session time zone. DateTime values are stored in the database as UTC.
3	Enabled. The values returned by the built-in time and date functions reflect the session time and session time zone. DateTime values without zone information are stored in the database as system local time. System local time offset is defined either using an SDF file and the tdlocaledef utility, or using the System TimeZone Hour and System TimeZone Minute DBS Control settings.

Default

2 for:

new Teradata Database systems.
systems that have been upgraded or re-initialized (sysinited) from prior Teradata Database releases in which TimeDateWZControl had been 0 and System TimeZone Hour or System TimeZone Minute had been non-zero.

For systems that have been upgraded or sysinited from prior Teradata Database releases in which TimeDateWZControl had been a non-zero value, that value remains unchanged after the upgrade or sysinit.

Changes Take Effect

After the DBS Control Record has been written.

Usage Notes

TimeDateWZControl must be enabled to use temporal tables. For more information on temporal tables, see Teradata Vantage™ - ANSI Temporal Table Support , B035-1186 and Teradata Vantage™ - Temporal Table Support , B035-1182 .

The session time zone can be set in the following ways:

TIME ZONE parameter of the CREATE USER statement
Sets the default time zone displacement from UTC used for sessions opened by the user.
SET TIME ZONE statement
Sets the time zone displacement from UTC for the current session. Overrides the time zone defined for the current user.

If no session time zone is defined in either of these ways, the session time zone defaults to the Teradata Database system time zone, as defined by the DBS Control fields System TimeZone Hour and System TimeZone Minute.

Examples: Using the TimeDateWZControl field of DBS Control

For the following examples, assume:

The time local to the Teradata Database server is 11:59:00 Coordinated Universal Time (UTC), January 31, 2010.
User TK lives in Tokyo, and has a time zone defined as +9 hours offset from UTC.
User LA lives in Los Angeles, and has a time zone defined as -8 hours offset from UTC.
User TK and User LA run the CURRENT_TIMESTAMP function at exactly the same time.

When this field is enabled:

For User TK, the CURRENT_TIMESTAMP function returns:

2010-02-01 20:59:00.000000+09:00

For User LA, the CURRENT_TIMESTAMP function returns:

2010-01-31 03:59:00.000000-08:00

When this field is disabled:

For User TK, the CURRENT_TIMESTAMP function returns:

2010-01-31 11:59:00.000000+09:00