Example: FNC_GetXMLByte and FNC_SetXMLByte - Teradata Vantage - Analytics Database

The following UDF takes an XML parameter as input, retrieves the XML value in binary form, and sets the return XML value in binary form. The UDF assumes the XML size is small enough to be read using a single read.

CREATE FUNCTION xmlUDF6(P1 XML)
RETURNS XML
NO SQL
PARAMETER STYLE SQL
DETERMINISTIC
LANGUAGE C
EXTERNAL NAME 'CS!xmlUDF6!xmlUDF6.c';

void xmlUDF6(XML_HANDLE* xml_handle,
             XML_HANDLE* return_handle,
             int* indicator_thisXML,
             int* indicator_returnValue,
             char    sqlstate[6],
             SQL_TEXT    extname[129],
             SQL_TEXT    specific_name[129],
             SQL_TEXT    error_message[257] )
{
     FNC_XMLSize_t xmlSize;
     byte* xmlBuffer;
     FNC_XMLSize_t xmlBufferSize;
     int numLobs;

    /* Get the XML Size */
      FNC_GetXMLInfo(*xml_handle, &xmlSize, &numLobs); 

     if(numLobs ==1 )
     {  /* Return null if a LOB is passed in */
        *indicator_returnValue = -1;
         return;
     }

    /* Read the XML value */
     xmlBuffer = (byte*)FNC_Malloc(xmlSize);
     xmlBufferSize = xmlSize;
      FNC_GetXMLByte(*xml_handle,xmlBuffer, xmlBufferSize, &xmlSize); 
                                                                                                                           
     /* Set the return value */
      FNC_SetXMLByte(*return_handle, xmlBuffer, xmlSize); 
    *indicator_returnValue = 0;
     FNC_free(xmlBuffer);
}