Session Temporal Qualifiers | Temporal Table Support | Teradata Vantage - 17.10 - Session Temporal Qualifiers - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Temporal Table Support

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1182-171K
Language
English (United States)

The SET SESSION statement lets you set session temporal qualifiers in the valid-time dimension, transaction-time dimension, or both dimensions. When a DML or SELECT statement refers to a temporal table but omits a temporal qualifier, the system uses the value of the session temporal qualifier.

A session temporal qualifier of CURRENT VALIDTIME AND CURRENT TRANSACTIONTIME allows applications written prior to the temporal capability to continue functioning without modifications in a non-temporal way on tables that may have been converted to temporal tables.

You can check the session temporal qualifier setting by looking at the Temporal Qualifier field of the output of the HELP SESSION statement. For more information on session temporal qualifiers, see SET SESSION (Session Temporal Qualifiers). For more information on HELP SESSION, see Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.

Best practice is to always use explicit temporal qualifiers on SELECT and DML statements that operate on temporal tables, rather than relying on the default temporal session qualifiers.