17.10 - Why Vantage Does Not Support The ANSI SQL STATE and RELATIVE Comparison Options - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Definition Language Detailed Topics

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1184-171K
Language
English (United States)

The ANSI SQL:2011 standard supports 3 comparison options for ordering definitions:

  • MAP
  • RELATIVE
  • STATE

Vantage does not support the STATE and RELATIVE comparisons because they do not mesh well with the Teradata parallel architecture. The issue that makes these options problematic is that there is a strong relationship between the concepts of equality and the hash values that Vantage generates for many of its join strategies. Two values that are equal in the relational use of the concept must generate hash values that are also equal.

The MAP ordering approach enables Vantage to generate internally an appropriate hash value for the UDT, enabling all Optimizer join strategies to function properly.