17.10 - Rules for Order Mapping Methods - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Definition Language Detailed Topics

Advanced SQL Engine
Teradata Database
Release Number
Release Date
July 2021
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, the system returns an error to the requestor.

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