Basic Scalar Function Definition | SQL External Routine Programming | Vantage - 17.10 - Basic Scalar Function Definition - 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)

Here are the basic steps you take to define a scalar function:

  1. Define the SQL_TEXT constant.

    For more information, see SQL_TEXT Definition.

  2. Include the sqltypes_td.h header file.

    For more information, see Header Files.

  3. Include other header files that define macros and variables that the function uses.
  4. Define the function parameter list in the order that matches the parameter passing convention specified in the CREATE FUNCTION statement.

    For more information, see Scalar Function Parameter List.

  5. Implement the function and set the result to the appropriate value.
  6. If the function detects an error, set the:
    • sqlstate argument to an SQLSTATE exception or warning condition before the function exits.

      For more information, see Returning SQLSTATE Values.

    • error_message string to the error message text. The characters must be inside the LATIN character range. The string is initialized to a null-terminated string on input.
  7. If the function uses parameter style SQL, set the indicator_result argument.
    IF the result is … THEN set the indicator_result argument to …
    NULL -1.
    not NULL 0.