17.10 - Example: Using FNC_GetXMLClob to Retrieve an XML Type Input Value - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - 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)

The following function takes an XML type parameter and retrieves the CLOB representation of the XML. It returns the CLOB back to the user.

CREATE FUNCTION xmlUDF2(P1 XML)
RETURNS CLOB AS LOCATOR
NO SQL
PARAMETER STYLE SQL
DETERMINISTIC
LANGUAGE C
EXTERNAL NAME 'CS!xmlUDF2!xmlUDF2.c';

void xmlUDF2(XML_HANDLE  *xml_handle,
              LOB_RESULT_LOCATOR *return_clob,
              int*       indicator_thisXML,
              int*       indicator_returnLOB,
              char       sqlstate[6],
              SQL_TEXT   extname[129],
              SQL_TEXT   specific_name[129],
              SQL_TEXT   error_message[257] )
{
     LOB_LOCATOR xmlClob;
     BYTE buffer[100000];
     LOB_CONTEXT_ID id;
     FNC_LobLength_t actlen;
     int trunc_err = 0;
     int numLobs;
     FNC_XMLSize_t xmlSize;
    
     FNC_GetXMLInfo(*xml_handle, &xmlSize, &numLobs);
  
      if(numLobs == 1) 
     {

      /* Read XML value */ 
       FNC_GetXMLClob(*xml_handle,&xmlClob); 

     /* Use LOB FNC calls to read the XML CLOB and return it */                                                                                                                           
      FNC_LobOpen(*xmlClob, &id, 0, 0);
      while( FNC_LobRead(id, buffer, 100000, &actlen) == 0 && !trunc_err)
          trunc_err = FNC_LobAppend(*return_clob, buffer, actlen, &actlen);

       FNC_LobClose(id);
      *indicator_returnLob = 0;
     }
 }