- User-defined functions.
- User-defined methods.
The ANSI SQL:2008 standard categorizes these SQL-invoked routines as either external routines or SQL routines.
An external routine is a user-defined function (UDF), method (UDM), or procedure that is written in an external, that is, non-SQL language such as C or C++, while SQL routines are written entirely in the SQL language.
When an external routine associated with a UDT is invoked, the system passes a handle to the UDT argument instead of passing the UDT value. Given the handle, the external routine can either retrieve or set the value of a UDT argument by means of a set of library functions provided by Teradata for this purpose. For more information, see Teradata Vantage™ - SQL External Routine Programming, B035-1147.