Example of retrieving a smart large object from the database using ifx_lo functions

The code example, loselect.c, shows how to retrieve a smart large object from the database.

You can find the loselect.c file in the %ONEDB_HOME%/demo/clidemo directory on UNIX™ platforms and in the %ONEDB_HOME%\demo\odbcdemo directory on Windows™ platforms. You can also find instructions on how to build the odbc_demo database in the same location.
/*
**    loselect.c
**
** To access a smart large object
**    SQLBindCol
**    SQLBindParameter
**    SQLConnect
**    SQLFetch
**    SQLFreeStmt
**    SQLGetInfo
**    SQLDisconnect
**    SQLExecDirect
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifndef NO_WIN32
#include <io.h>
#include <windows.h>
#include <conio.h>
#endif /*NO_WIN32*/

#include "infxcli.h"

#define ERRMSG_LEN  200

UCHAR   defDsn[] = "odbc_demo";

int checkError (SQLRETURN     rc,
               SQLSMALLINT    handleType,
               SQLHANDLE      handle,
               char           *errmsg)
{
   SQLRETURN   retcode = SQL_SUCCESS;

   SQLSMALLINT errNum = 1;
   SQLCHAR     sqlState[6];
   SQLINTEGER  nativeError;
   SQLCHAR     errMsg[ERRMSG_LEN];
   SQLSMALLINT textLengthPtr;


   if ((rc != SQL_SUCCESS) && (rc != SQL_SUCCESS_WITH_INFO))
   {
      while (retcode != SQL_NO_DATA)
      {
         retcode = SQLGetDiagRec (handleType, handle, errNum, sqlState,
               &nativeError, errMsg, ERRMSG_LEN, &textLengthPtr);

         if (retcode == SQL_INVALID_HANDLE)
         {
            fprintf (stderr, "checkError function was called with an
               invalid handle!!\n");
            return 1;
         }

         if ((retcode == SQL_SUCCESS) || (retcode ==
               SQL_SUCCESS_WITH_INFO))
            fprintf (stderr, "ERROR: %d:  %s : %s \n", nativeError,
                  sqlState, errMsg);

         errNum++;
      }

      fprintf (stderr, "%s\n", errmsg);
      return 1;   /* all errors on this handle have been reported */
   }
   else
      return 0;   /* no errors to report */
}

int main (long    argc,
         char     *argv[])
{
   /* Declare variables
   */

   /* Handles */
   SQLHDBC     hdbc;
   SQLHENV     henv;
   SQLHSTMT    hstmt;

   /* Smart large object file descriptor */
   long        lofd;
   long           lofd_valsize = 0;

   /* Smart large object pointer structure */
   char*       loptr_buffer;
   short       loptr_size;
   long        loptr_valsize = 0;

   /* Smart large object status structure */
   char*       lostat_buffer;
   short       lostat_size;
   long        lostat_valsize = 0;

   /* Smart large object data */
   char*       lo_data;
   long        lo_data_valsize = 0;

   /* Miscellaneous variables */
   UCHAR       dsn[20]; /*name of the DSN used for connecting to the
                  database*/
   SQLRETURN   rc = 0;
   int         in;

   char*       selectStmt = "SELECT advert FROM item WHERE item_num =
                  1004";
   long        mode = LO_RDONLY;
   long        lo_size;
   long        cbMode = 0, cbLoSize = 0;


/* STEP 1.  Get data source name from command line (or use default)
   **       Allocate the environment handle and set ODBC version
   **       Allocate the connection handle
   **       Establish the database connection
   **       Allocate the statement handle
   */

   /* If(dsn is not explicitly passed in as arg) */
   if (argc != 2)
   {
      /* Use default dsn - odbc_demo */
      fprintf (stdout, "\nUsing default DSN : %s\n", defDsn);
      strcpy ((char *)dsn, (char *)defDsn);
   }
   else 
   {
      /* Use specified dsn */
      strcpy ((char *)dsn, (char *)argv[1]);
      fprintf (stdout, "\nUsing specified DSN : %s\n", dsn);
   }

   /* Allocate the Environment handle */
   rc = SQLAllocHandle (SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);
   if (rc != SQL_SUCCESS)
   {
      fprintf (stdout, "Environment Handle Allocation
            failed\nExiting!!\n");
      return (1);
   }

   /* Set the ODBC version to 3.5 */
   rc = SQLSetEnvAttr (henv, SQL_ATTR_ODBC_VERSION,
         (SQLPOINTER)SQL_OV_ODBC3, 0);
   if (checkError (rc, SQL_HANDLE_ENV, henv, "Error in Step 1 --
         SQLSetEnvAttr failed\nExiting!!\n"))
      return (1);

   /* Allocate the connection handle */
   rc = SQLAllocHandle (SQL_HANDLE_DBC, henv, &hdbc);
   if (checkError (rc, SQL_HANDLE_ENV, henv, "Error in Step 1 -- Connection
         Handle Allocation failed\nExiting!!\n"))
      return (1);

   /* Establish the database connection */
   rc = SQLConnect (hdbc, dsn, SQL_NTS, "", SQL_NTS, "", SQL_NTS);
   if (checkError (rc, SQL_HANDLE_DBC, hdbc, "Error in Step 1 -- SQLConnect
         failed\nExiting!!"))
      return (1);
   /* Allocate the statement handle */
   rc = SQLAllocHandle (SQL_HANDLE_STMT, hdbc, &hstmt);
   if (checkError (rc, SQL_HANDLE_DBC, hdbc, "Error in Step 1 -- Statement
         Handle Allocation failed\nExiting!!"))
      return (1);

   fprintf (stdout, "STEP 1 done...connected to database\n");


/* STEP 2.  Select a smart-large object from the database
   **       -- the select statement executed is -
   **       "SELECT advert FROM item WHERE item_num = 1004"
   */

   /* Execute the select statement */
   rc = SQLExecDirect (hstmt, selectStmt, SQL_NTS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 2 --
         SQLExecDirect failed\n"))
      goto Exit;

   fprintf (stdout, "STEP 2 done...select statement executed...smart large
         object retrieved from the databse\n");


/* STEP 3.  Get the size of the smart large object pointer structure.
   **       Allocate a buffer to hold the structure.
   **       Get the smart large object pointer structure from the
   **       database.
   **       Close the result set cursor.
   */

   /* Get the size of the smart large object pointer structure */
   rc = SQLGetInfo (hdbc, SQL_INFX_LO_PTR_LENGTH, &loptr_size,
         sizeof(loptr_size),
         NULL);
   if (checkError (rc, SQL_HANDLE_DBC, hdbc, "Error in Step 3 -- SQLGetInfo
         failed\n"))
      goto Exit;

   /* Allocate a buffer to hold the smart large object pointer structure */
   loptr_buffer = malloc (loptr_size);

   /* Bind the smart large object pointer structure buffer allocated to the
         column in the result set & fetch it from the database */
   rc = SQLBindCol (hstmt, 1, SQL_C_BINARY, loptr_buffer, loptr_size,
         &loptr_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 3 --
         SQLBindCol failed\n"))
      goto Exit;

   rc = SQLFetch (hstmt);
   if (rc == SQL_NO_DATA_FOUND)
   {
      fprintf (stdout, "No Data Found\nExiting!!\n");
      goto Exit;
   }
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 3 -- SQLFetch
         failed\n"))
      goto Exit;

   /* Close the result set cursor */
   rc = SQLCloseCursor (hstmt);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 3 --
         SQLCloseCursor failed\n"))
      goto Exit;

   fprintf (stdout, "STEP 3 done...smart large object pointer structure
      fetched from the database\n");


/* STEP 4.  Use the smart large object's pointer structure to open it
   **       and obtain the smart large object file descriptor.
   **       Reset the statement parameters.
   */

   rc = SQLBindParameter (hstmt, 1, SQL_PARAM_OUTPUT, SQL_C_LONG,
         SQL_INTEGER, (UDWORD)0, 0, &lofd, sizeof(lofd), &lofd_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 4 --
         SQLBindParameter failed (param 1)\n"))
      goto Exit;

   rc = SQLBindParameter (hstmt, 2, SQL_PARAM_INPUT, SQL_C_BINARY,
         SQL_INFX_UDT_FIXED, (UDWORD)loptr_size, 0, loptr_buffer,
         loptr_size, &loptr_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 4 --
         SQLBindParameter failed (param 2)\n"))
      goto Exit;

   rc = SQLBindParameter (hstmt, 3, SQL_PARAM_INPUT, SQL_C_LONG,
         SQL_INTEGER, (UDWORD)0, 0, &mode, sizeof(mode), &cbMode);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 4 --
         SQLBindParameter failed (param 3)\n"))
      goto Exit;

   rc = SQLExecDirect (hstmt, "{? = call ifx_lo_open(?, ?)}", SQL_NTS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 4 --
         SQLExecDirect failed\n"))
      goto Exit;

   /* Reset the statement parameters */
   rc = SQLFreeStmt (hstmt, SQL_RESET_PARAMS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 4 --
         SQLFreeStmt failed\n"))
      goto Exit;

   fprintf (stdout, "STEP 4 done...smart large object opened... file
         descriptor obtained\n");


/* STEP 5.  Get the size of the smart large object status structure.
   **       Allocate a buffer to hold the structure.
   **       Get the smart large object status structure from the
   **       database.
   **       Reset the statement parameters.
   */

   /* Get the size of the smart large object status structure */
   rc = SQLGetInfo (hdbc, SQL_INFX_LO_STAT_LENGTH, &lostat_size,
         sizeof(lostat_size), NULL);
   if (checkError (rc, SQL_HANDLE_DBC, hdbc, "Error in Step 5 -- SQLGetInfo
         failed\n"))
      goto Exit;

   /* Allocate a buffer to hold the smart large object status structure. */
   lostat_buffer = malloc(lostat_size);

   /* Get the smart large object status structure from the database. */
   rc = SQLBindParameter (hstmt, 1, SQL_PARAM_INPUT, SQL_C_LONG,
         SQL_INTEGER, (UDWORD)0, 0, &lofd, sizeof(lofd), &lofd_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 5 --
         SQLBindParameter failed (param 1)\n"))
      goto Exit;

   rc = SQLBindParameter (hstmt, 2, SQL_PARAM_INPUT_OUTPUT, SQL_C_BINARY,
         SQL_INFX_UDT_FIXED, (UDWORD)lostat_size, 0, lostat_buffer,
         lostat_size, &lostat_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 5 --
         SQLBindParameter failed (param 2)\n"))
      goto Exit;

   rc = SQLExecDirect (hstmt, "{call ifx_lo_stat(?, ?)}", SQL_NTS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 5 --
         SQLExecDiret failed\n"))
      goto Exit;

   /* Reset the statement parameters */
   rc = SQLFreeStmt (hstmt, SQL_RESET_PARAMS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 5 --
         SQLFreeStmt failed\n"))
      goto Exit;

   fprintf (stdout, "STEP 5 done...smart large object status structure
         fetched from the database\n");


/* STEP 6.  Use the smart large object's status structure to get the
   **       size of the smart large object.
   **       Reset the statement parameters.
   */

   /* Use the smart large object status structure to get the size of the
         smart large object */
   rc = SQLBindParameter (hstmt, 1, SQL_PARAM_INPUT, SQL_C_BINARY,
         SQL_INFX_UDT_FIXED, (UDWORD)lostat_size, 0, lostat_buffer,
         lostat_size, &lostat_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 6 --
         SQLBindParameter failed (param 1)\n"))
      goto Exit;

   rc = SQLBindParameter (hstmt, 2, SQL_PARAM_OUTPUT, SQL_C_LONG,
         SQL_BIGINT, (UDWORD)0, 0, &lo_size, sizeof(lo_size), &cbLoSize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 6 --
         SQLBindParameter failed (param 1)\n"))
      goto Exit;

   rc = SQLExecDirect (hstmt, "{call ifx_lo_stat_size(?, ?)}", SQL_NTS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 6 --
         SQLExecDirect failed\n"))
      goto Exit;

   /* Reset the statement parameters */
   rc = SQLFreeStmt (hstmt, SQL_RESET_PARAMS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 6 --
         SQLFreeStmt failed\n"))
      goto Exit;

   fprintf (stdout, "STEP 6 done...smart large object size = %ld bytes\n",
         lo_size);


/* STEP 7.  Allocate a buffer to hold the smart large object's data.
   **       Read the smart large object's data using its file descriptor.
   **       Null-terminate the last byte of the smart large-object's data.
   **       Print out the contents of the smart large object.
   **       Reset the statement parameters.
   */

   /* Allocate a buffer to hold the smart large object's data chunks */
   lo_data = malloc (lo_size + 1);

   /* Read the smart large object's data */
   rc = SQLBindParameter (hstmt, 1, SQL_PARAM_INPUT, SQL_C_LONG,
         SQL_INTEGER, (UDWORD)0, 0, &lofd, sizeof(lofd), &lofd_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 7 --
         SQLBindParameter failed (param 1)\n"))
      goto Exit;

   rc = SQLBindParameter (hstmt, 2, SQL_PARAM_OUTPUT, SQL_C_CHAR, SQL_CHAR,
         lo_size, 0, lo_data, lo_size, &lo_data_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 7 --
         SQLBindParameter failed (param 2)\n"))
      goto Exit;

   rc = SQLExecDirect (hstmt, "{call ifx_lo_read(?, ?)}", SQL_NTS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 7 --
         SQLExecDirect failed\n"))
      goto Exit;

   /* Null-terminate the last byte of the smart large objects data */
   lo_data[lo_size] = '\0';

   /* Print the contents of the smart large object */
   fprintf (stdout, "Smart large object contents are.....\n\n\n%s\n\n\n",
         lo_data);

   /* Reset the statement parameters */
   rc = SQLFreeStmt (hstmt, SQL_RESET_PARAMS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 7 --
         SQLFreeStmt failed\n"))
      goto Exit;

   fprintf (stdout, "STEP 7 done...smart large object read completely\n");



/* STEP 8.  Close the smart large object.
   */

   rc = SQLBindParameter (hstmt, 1, SQL_PARAM_INPUT, SQL_C_LONG,
         SQL_INTEGER, (UDWORD)0, 0, &lofd, sizeof(lofd), &lofd_valsize);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 8 --
         SQLBindParameter failed\n"))
      goto Exit;

   rc = SQLExecDirect (hstmt, "{call ifx_lo_close(?)}", SQL_NTS);
   if (checkError (rc, SQL_HANDLE_STMT, hstmt, "Error in Step 8 --
         SQLExecDirect failed\n"))
      goto Exit;

   fprintf (stdout, "STEP 8 done...smart large object closed\n");


/* STEP 9.  Free the allocated buffers.
   */

   free (loptr_buffer);
   free (lostat_buffer);
   free (lo_data);

   fprintf (stdout, "STEP 9 done...smart large object buffers freed\n");

   Exit:

   /* CLEANUP: Close the statement handle
   **          Free the statement handle
   **          Disconnect from the datasource
   **          Free the connection and environment handles
   **          Exit
   */

   /* Close the statement handle */
   SQLFreeStmt (hstmt, SQL_CLOSE);

   /* Free the statement handle */
   SQLFreeHandle (SQL_HANDLE_STMT, hstmt);

   /* Disconnect from the data source */
   SQLDisconnect (hdbc);

   /* Free the environment handle and the database connection handle */
   SQLFreeHandle (SQL_HANDLE_DBC, hdbc);
   SQLFreeHandle (SQL_HANDLE_ENV, henv);

   fprintf (stdout,"\n\nHit <Enter> to terminate the program...\n\n");
   in = getchar ();
   return (rc);
}