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

Teradata Vantage™ - SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
16.20
Release Date
April 2020
Content Type
Programming Reference
Publication ID
B035-1147-162K
Language
English (United States)

UDFs can define CLOB or BLOB arguments and return values, passing them by locator.

Here is an example of how to declare a scalar function that uses LOB types.

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

The corresponding CREATE FUNCTION statement looks like this:

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

For details on the LOB_LOCATOR and LOB_RESULT_LOCATOR C data types, see C Data Types.