Catalog ActiveConnection Property Example (VC++)

Setting the ActiveConnection property to a valid, open connection "opens" the catalog. From an open catalog, you can access the schema objects contained within that catalog.

// BeginActiveConnectionCpp
#import "c:\Program Files\Common Files\system\ado\msado15.dll"
#import "c:\Program Files\Common Files\system\ado\msadox.dll" \
    no_namespace

#include "iostream.h"
#include "stdio.h"
#include "conio.h"

// Function declarations
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void OpenConnectionX(void);
void OpenConnectionWithStringX(void);

//////////////////////////////////////////////////////////
//                                                      //
//         Main Function                                //
//                                                      //
//////////////////////////////////////////////////////////
void main()
{
    if(FAILED(::CoInitialize(NULL)))
        return;

    OpenConnectionX();

    OpenConnectionWithStringX();

    ::CoUninitialize();
}

//////////////////////////////////////////////////////////
//                                                      //
//     OpenConnectionX Function                         //
//                                                      //
//////////////////////////////////////////////////////////
void OpenConnectionX(void) 
{
   HRESULT   hr = S_OK;

    // Define ADOX object pointers.
    // Initialize pointers on define.
    // These are in the ADOX::  namespace.    
    _CatalogPtr m_pCatalog = NULL;

    //Define ADODB object pointers
    ADODB::_ConnectionPtr m_pCnn   = NULL;
   
    // Define string variables.
    _bstr_t strcnn("Provider='Microsoft.JET.OLEDB.4.0';"
        "Data source = 'c:\\Program Files\\Microsoft Office\\"
        "Office\\Samples\\Northwind.mdb';");

    try
    {
        TESTHR(hr = m_pCnn.CreateInstance(__uuidof(ADODB::Connection)));
        TESTHR(hr = m_pCatalog.CreateInstance(__uuidof (Catalog)));
        m_pCnn->Open(strcnn,"","",NULL);
        m_pCatalog->PutActiveConnection(_variant_t((IDispatch *) m_pCnn));
        _variant_t vIndex = (short) 0;
        cout<<m_pCatalog->Tables->GetItem(vIndex)->Type<<endl;
    }
    catch(_com_error &e)
    {
        // Notify the user of errors if any.
        _bstr_t bstrSource(e.Source());
        _bstr_t bstrDescription(e.Description());

        printf("\n\tSource :  %s \n\tdescription : %s \n ",
            (LPCSTR)bstrSource,(LPCSTR)bstrDescription);
    }
    catch(...)
    {
        cout << "Error occured in OpenConnectionX...."<< endl;
    }

    if (m_pCnn)
        if (m_pCnn->State == 1)
            m_pCnn->Close();
}

//////////////////////////////////////////////////////////
//                                                      //
//         OpenConnectionWithStringX Function           //
//                                                      //
//////////////////////////////////////////////////////////
void OpenConnectionWithStringX(void) 
{
    HRESULT   hr = S_OK;

    // Define ADOX object pointers.
    // Initialize pointers on define.
    // These are in the ADOX::  namespace.
    _CatalogPtr m_pCatalog = NULL;
  
    // Define string variables.
    _bstr_t strcnn("Provider='Microsoft.JET.OLEDB.4.0';"
                "Data source = 'c:\\Program Files\\Microsoft Office\\"
                "Office\\Samples\\Northwind.mdb';");

    try
    {
        TESTHR(hr = m_pCatalog.CreateInstance(__uuidof (Catalog)));
        m_pCatalog->PutActiveConnection(strcnn);
        _variant_t vIndex = (short) 0;
        cout<<m_pCatalog->Tables->GetItem(vIndex)->Type<<endl;
    }
    catch(_com_error &e)
    {
        // Notify the user of errors if any.
        _bstr_t bstrSource(e.Source());
        _bstr_t bstrDescription(e.Description());

        printf("\n\tSource :  %s \n\tdescription : %s \n ",
           (LPCSTR)bstrSource,(LPCSTR)bstrDescription);
    }
    catch(...)
    {
        cout << "Error occured in OpenConnectionWithStringX...."<< endl;
    }
}
// EndActiveConnectionCpp

See Also

ActiveConnection Property