Rules for Order Mapping Methods
If you specify a method as the MAP routine for an ordering, it must obey the following
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:
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 aborts the request and returns an error
to the requestor.
See “CREATE METHOD” on page 403 for details about method associations with UDTs, parameters, result data types, and
the DETERMINISTIC option.