17.10 - Function Parameter List - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1147-171K
Language
English (United States)

UDFs can define UDT arguments and return values, passing them by UDT handle. Here is an example of how to declare a scalar function that uses UDT types:

/*****  C source file name: udfsamp.c  *****/
   
#define SQL_TEXT Latin_Text
#include <sqltypes_td.h>
   
void do_something( UDT_HANDLE          *aUDT,
                   UDT_HANDLE          *resultUDT,
                   char                sqlstate[6] )
{
     ...
}

Suppose you create a structured UDT called circleUDT that you want to use as the input parameter and return type for the do_something function. The corresponding CREATE FUNCTION statement looks like this:

CREATE FUNCTION DO_SOMETHING(A circleUDT)
        RETURNS circleUDT
        LANGUAGE C
        NO SQL
        PARAMETER STYLE TD_GENERAL
        EXTERNAL NAME 'CS!udfsamp!td_udf/udfsamp.c';

To use a dynamic UDT as the input parameter, the corresponding CREATE FUNCTION statement looks like this:

CREATE FUNCTION DO_SOMETHING(A VARIANT_TYPE)
        RETURNS circleUDT
        LANGUAGE C
        NO SQL
        PARAMETER STYLE TD_GENERAL
        EXTERNAL NAME 'CS!udfsamp!td_udf/udfsamp.c';

For details on the UDT_HANDLE C data type, see C Data Types.