16.20 - Rules for Order Mapping Methods - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Definition Language Detailed Topics

Teradata Database
Teradata Vantage NewSQL Engine
Release Number
March 2019
Content Type
Programming Reference
Publication ID
English (United States)
If you specify a method as the MAP routine for an ordering, it must obey the following rules:
  • It must be associated with the UDT for which this ordering is defined.
  • Its declared parameter list must be empty.
  • Its result data type must be a predefined data type.

    Its predefined data type is valid except the following:

    • BLOB
    • CLOB
  • It must be declared to be DETERMINISTIC.
  • The name you specify for it in the ordering definition must be the name of a method contained within the SYSUDTLIB database.
  • If you create a structured UDT that might be used for a hash index definition, you must ensure that its ordering function never returns a null. If it does, Teradata Database returns an error to the requestor.

See CREATE METHOD for details about method associations with UDTs, parameters, result data types, and the DETERMINISTIC option.