Creating Netezza User Defined Functions in C++

STEPS TO CREATE NETEZZA UDF

For creating UDF in netezza we should have knowledge of C++ programming. The post explains how to create netezza UDF which finds greater value out of two values passed.

STEP 1 :

Write C++ code for the function. The code refers the the below header files.

#include "udxinc.h"

#include "udxhelpers.h"

 And namespace list is mentioned below

using namespace nz::udx::dthelpers;

using namespace nz::udx;

The sample code for the greater of two numbers is mentioned below.

#include "udxinc.h"

#include "udxhelpers.h"

#include <ctype.h>

using namespace nz::udx;

class greaterOfTwo : public Udf

{

  public:

    static Udf* instantiate();

    virtual ReturnValue evaluate()

    {

      int64 first = int64Arg(0);

      int64 second = int64Arg(1);

      int64 returnValue = 0;

      if (first > second) returnValue = first; else returnValue = second;

      NZ_UDX_RETURN_INT64(returnValue);

    }

};

Udf* greaterOfTwo::instantiate()

{

  return new greaterOfTwo();

}

STEP 2:
We use the netezza command line utility (nzudxcompile) to compile the C++ code. The sample code to compile the C++ code is mentioned below.

NZ_DATABASE=MYDB;

nzudxcompile -g --sig "greaterOfTwo(bigint,bigint)" --return "bigint" --class greaterOfTwo /export/home/user/mydata/greatest.cpp