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

SQL Data Definition Language Detailed Topics

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Published
July 2021
Language
English (United States)
Last Update
2021-07-27
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imq1591724555718.ditamap
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dita:id
B035-1184
lifecycle
previous
Product Category
Teradata Vantage™

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.