Setting module name in OCI program

Question

Hi,
I have been struggling with setting the module name from my OCI program. Below is the code in which
I create the environment, connect, attempt to set the module attribute, wait for key input, and clean up
and exit after getting the key input.
That I can tell, I have called OCISetAttr as the documentation says I should and none of my return values
indicate a problem. Yet when I v$session, I get what I presume is the default value of the module
and not the value I set in the code("moduletest").
The programs physical filename is oci101.exe. It also connects to the Oracle instance as a user named
oci101. I check v$session with this query:
select username, module from v$session where username is not null;
And the output is this:
USERNAME MODULE
OCI101 oci101.exe
SYSTEM SQL*Plus
I should see a MODULE column value of "moduletest" for the OCI101 user.
Not sure what I'm missing. Any ideas?? Here is the code:
// Begin code:
OCIEnv* envhp;
ub2 charset_id = 0;
ub2 ncharset_id = 0;
ub4 mode = OCI_DEFAULT;
const sword env_rc = OCIEnvNlsCreate(
&envhp, mode,
(void*)0, // user-defined context for custom memory allocation
(void* (*)(void*, size_t))0, // user-defined malloc
(void* (*)(void*, void *, size_t))0, // user-defined realloc
(void(*)(void*, void*))0, // // user-defined free
(size_t)0, // extra user memory
(void **)0,
charset_id, ncharset_id
OCIError* errhp;
const sword err_rc = OCIHandleAlloc(
(dvoid *) envhp, (dvoid **) &errhp,
OCI_HTYPE_ERROR, (size_t) 0, (dvoid **) 0
checkerr(err_rc, errhp);
OCISvcCtx* svchp = 0;
const sword l2rc = OCILogon2(
envhp, errhp, &svchp,
(const OraText*)zusername, (ub4)strlen(zusername),
(const OraText*)zpassword, (ub4)strlen(zpassword),
(const OraText*)zdatabase, (ub4)strlen(zdatabase),
mode
checkerr(l2rc, errhp);
// Set the module attrbute
// Extract the session handle into sessionhp.
OCISession *sessionhp = 0;
ub4 sh_size = 0;
sword oci_attr_get_status = OCIAttrGet ( svchp,
OCI_HTYPE_SVCCTX,
&sessionhp,
&sh_size,
OCI_ATTR_SESSION,
errhp );
checkerr(oci_attr_get_status, errhp);
// Set the module
sword oas_rc = OCIAttrSet(sessionhp, OCI_HTYPE_SESSION,(void *)"moduletest",
strlen("moduletest"), OCI_ATTR_MODULE, errhp);
checkerr(oas_rc, errhp);
getchar();
// Cleanup:
if (svchp) { // 0 when already disconnected
OCISvcCtx*const tmp_svchp = svchp;
svchp = 0; // reset svchp on error or not
const sword lorc = OCILogoff(tmp_svchp, errhp);
checkerr(lorc, errhp);
const sword rc = OCIHandleFree(envhp, OCI_HTYPE_ENV);
// End Code.
Thanks for any help . . .
Karl

Answer 1

Hi Karl,
I'm certainly not an OCI expert, but after setting the module attribute the value is updated upon the next statement execution in my experience. There may be other ways in which this can happen, but I have not seen those cases.
Here is a short example:
#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <oci.h>
int main(int argc, char *argv[]) {
  OCIEnv      *envhp = NULL;  /* OCI Environment handle     */
  OCIError    *errhp = NULL;  /* OCI Error handle           */
  OCISvcCtx   *svchp = NULL;  /* OCI Service Context handle */
  OCISession  *usrhp = NULL;  /* OCI User Session handle    */
  OCIStmt     *stmtp = NULL;  /* OCI Statement handle       */
  /* the statement to execute   */
  /* this is purely for example */
  oratext *sqlstmt = "begin null; end;";
  /* connection information */
  oratext *username = "scott";
  oratext *password = "tiger";
  oratext *database = "orademo";
  /* used to hold the results of each OCI call */
  sword result = 0;
  /* Initialize and create a default environment */
  result = OCIEnvCreate(&envhp,
                        OCI_DEFAULT,
                        (dvoid *) 0,
                        0,
                        0,
                        0,
                        (size_t) 0,
                        (dvoid **) 0);
  /* allocate an error handle */
  result = OCIHandleAlloc((dvoid *) envhp,
                          (dvoid **) &errhp,
                          OCI_HTYPE_ERROR,
                          0,
                          (dvoid **) 0);
  /* create connection */
  result = OCILogon2(envhp,
                     errhp,
                     &svchp,
                     username,
                     (ub4) strlen(username),
                     password,
                     (ub4) strlen(password),
                     database,
                     (ub4) strlen(database),
                     OCI_DEFAULT);
  /* get the user session handle */
  result = OCIAttrGet(svchp,
                      OCI_HTYPE_SVCCTX,
                      (void *) &usrhp,
                      NULL,
                      OCI_ATTR_SESSION,
                      errhp);
  /* set the module attribute */
  result = OCIAttrSet(usrhp,
                      OCI_HTYPE_SESSION,
                      (void *) "My Module",
                      (ub4) strlen("My Module"),
                      OCI_ATTR_MODULE,
                      errhp);
  /* allocate the statement handle */
  result = OCIHandleAlloc((dvoid *) envhp,
                          (dvoid **) &stmtp,
                          OCI_HTYPE_STMT,
                          0,
                          (dvoid **) 0);
  /* prepare the statement for execution */
  result = OCIStmtPrepare(stmtp,
                          errhp,
                          sqlstmt,
                          (ub4) strlen((char *) sqlstmt),
                          OCI_NTV_SYNTAX,
                          OCI_DEFAULT);
  /* execute the statement - after execution the */
  /* MODULE value should be updated in v$session */
  result = OCIStmtExecute(svchp,
                          stmtp,
                          errhp,
                          (ub4) 1,
                          (ub4) 0,
                          (CONST OCISnapshot *) NULL,
                          (OCISnapshot *) NULL,
                          OCI_DEFAULT);
  /* print a simple prompt    */
  /* view session in SQL*Plus */
  printf("program paused, ENTER to continue...");
  getchar();
  /* disconnect from the server */
  result = OCILogoff(svchp,
                     errhp);
  /* deallocate the environment handle */
  /* OCI will deallocate child handles */
  result = OCIHandleFree((void *) envhp,
                         OCI_HTYPE_ENV);
  return OCI_SUCCESS;
}When the program is paused I see this in SQL*Plus in my test:
SQL> select sid, username, program, module from v$session where username = 'SCOTT';
       SID USERNAME         PROGRAM                          MODULE
       136 SCOTT            OCIModuleTest.exe                My ModulePerhaps that is a bit of help.
Regards,
Mark
Edited by: Mark Williams on Dec 22, 2008 11:06 AM
Tidied up the sample a bit.