Thread: Connecting to Oracle Problem

Let me preface by saying Im not really a C programmer. More of a vb programmer doing .net stuff, but someone got word i did a little c back in college some 10 years ago and threw this at me. so im not really comfortable or sure i know what im doing.

they are trying to connect to an oracle database we have here. using that data source, username, and pass in the connstring i can connect to the database using sql+. The code they gave me was a mess, so ive cleaned it up a bit and finally got it to compile. it crashes on the pConnection->Open line, and my catch message simple says "Invalid Pointer". Ive found a lot of very similar code on the net so I know im not doing anything too unordinary. Any ideas or can someone please point me in the right direction?

Thanks

Code:

#include <iostream>
#include <stdio.h>
#include <windows.h>

#import "C:\Program Files\Common Files\System\ADO\msado15.dll" no_namespace rename("EOF", "EndOfFile")

//#include "c:\oracle\ora92\oo4o\CPP\include\ORACL.H"
//#include "c:\oracle\ora92\oledb\include\oraoledb.h"

using namespace std;

void main()
{    
	HRESULT hr = S_OK;

	_ConnectionPtr pConnection = NULL;

	_bstr_t strCnn("Provider=OraOLEDB.Oracle;PLSQLRSet=1;USER Id=UPTS_TEST;Password=UPTS_TEST;Data Source=DVLP9;");

    try
    {
        /* create an instance of connection object */

        //TESTHR (pConnection.CreateInstance(__uuidof(Connection)));      

        /* open the connection */
		hr = pConnection.CreateInstance(__uuidof(Connection));
		cout << "before connect\n";
        hr = pConnection->Open(strCnn,"","",adConnectUnspecified);  
		cout << "after connect\n";
        if (hr == S_OK)
            cout << "connected\n";
        else
            cout << "not connected\n";  
		pConnection->Close();
	}
	catch(_com_error &ce)
    {
		printf("Description = %s\n", (char*) ce.ErrorMessage()); 
    }
}

Code:

hr = pConnection.CreateInstance(__uuidof(Connection));

Set a breakpoint on the line after this one, debug and tell me what the values of hr and pConnection are.

Originally Posted by Salem

Does this even compile?

Welcome to the wacky world of COM objects.

RvS, after looking through some old code of mine, I believe you are missing:-

Code:

CoInitialize(NULL);

At the start of main and

Code:

CoUninitialize();

at the end.

very good. i will try that first thing in the morning. thanks so much

The reason why you are getting an invalid pointer, is that the pointer isn't initiated via createinstance():
HRESULT hr = pConnection->CreateInstance(__uuidof(ADODB::Connection));

Originally Posted by SMurf

Welcome to the wacky world of COM objects.

RvS, after looking through some old code of mine, I believe you are missing:-

Code:

CoInitialize(NULL);

At the start of main and

Code:

CoUninitialize();

at the end.

SMurf,
worked like a charm, thanks so much!