MDAC 2.5 SDK - ADO

Attributes and Name Properties Example (VC++)

See Also

This example displays the value of the Attributes property for Connection, Field, and Property objects. It uses the Name property to display the name of each Field and Property object.

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

#include <ole2.h>
#include <stdio.h>
#include<conio.h>

// Function declarations
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void AttributesX();
void PrintProviderError(_ConnectionPtr pConnection);
void PrintComError(_com_error &e);

///////////////////////////////////////////////////////////
//                                                       //
//      Main Function                                    //
//                                                       //
///////////////////////////////////////////////////////////

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

    AttributesX();

    ::CoUninitialize();
}

///////////////////////////////////////////////////////////
//                                                       //
//      AttributesX Function                             //
//                                                       //
///////////////////////////////////////////////////////////

void AttributesX()
{
    // Define ADO object pointers.
    // Initialize pointers on define.
    // These are in the ADODB::  namespace
    _RecordsetPtr   pRstEmployee  = NULL;
    _ConnectionPtr pConnection = NULL;
    FieldsPtr  fldLoop = NULL;    
    PropertiesPtr proLoop = NULL;

    //Define Other Variables
    HRESULT  hr = S_OK;
    _variant_t Index;
    Index.vt = VT_I2;
    int j=0;      
    //Open a recordset using a Client Cursor
    //For the Employee Table
    _bstr_t strCnn("Provider=sqloledb;Data Source=srv;"
        "Initial Catalog=Pubs;User Id=sa;Password=;");

    try
    {
        // open connection and record set
        TESTHR(pConnection.CreateInstance(__uuidof(Connection)));
        pConnection->Open(strCnn,"","",NULL);
        
        TESTHR(pRstEmployee.CreateInstance(__uuidof(Recordset)));
        pRstEmployee->Open("Employee", 
            _variant_t((IDispatch *)pConnection,true), adOpenForwardOnly,
            adLockReadOnly, adCmdTable);

        // Display the attributes of the Connection.
        printf("Connection attributes: %d \n", pConnection->Attributes);

        // Display the attributes of the employee table's fields
        printf("\nFields attributes:\n");
        fldLoop = pRstEmployee->GetFields();

        for (int i = 0; i < (int)fldLoop->GetCount(); i++)
        {
            Index.iVal=i;
            printf ("   %s = %d \n",
                (LPSTR)fldLoop->GetItem(Index)->GetName(),
                (int)fldLoop->GetItem(Index)->GetAttributes());
        }

        // Display Fields of the Employee table which are NULLBALE
        printf("\nNULLABLE Fields :");
        
        for (int i1 = 0; i1 < (int)fldLoop->GetCount(); i1++)
        {
            Index.iVal = i1;
            
            if (fldLoop->GetItem(Index)->GetAttributes() & 
                    adFldIsNullable)
                {
                    printf ("%s  \n",LPSTR)fldLoop->GetItem(Index)->
                                GetName());
                }
        }

        // Display the attributes of the Employee tables's 
        // properties
        printf("\nProperty attributes:\n");
        proLoop = pRstEmployee->GetProperties();
      
        for (int i2 = 0; i2 < (int)proLoop->GetCount(); i2++)
        {
            j= j+1;
            Index.iVal=i2;
            printf (" %s = %d \n", 
                (LPSTR)(_bstr_t)proLoop->GetItem(Index)->GetName(),
                (int)proLoop->GetItem(Index)->GetAttributes());

            if (((j % 23) == 0) || ( i2==6))
            {
                printf("\nPress any key to continue...");
                getch();

                //Clear the screen for the next display   
                system("cls"); 
                j=0;
            }
        }
        // Clean up objects before exit.
        pRstEmployee->Close();
        pConnection->Close();
    }

    catch(_com_error &e)
    {
        // Notify the user of errors if any.
        
        PrintProviderError(pConnection);
        PrintComError(e);
    }
}

///////////////////////////////////////////////////////////
//                                                       //
//      PrintProviderError Function                      //
//                                                       //
///////////////////////////////////////////////////////////

void PrintProviderError(_ConnectionPtr pConnection)
{
    // Print Provider Errors from Connection object.

    // pErr is a record object in the Connection's Error collection.
    ErrorPtr  pErr  = NULL;
    long      nCount  = 0;
    long      i    = 0;

    if( (pConnection->Errors->Count) > 0)
    {
        nCount = pConnection->Errors->Count;

        // Collection ranges from 0 to nCount -1.
        for(i = 0; i < nCount; i++)    
        {
            pErr = pConnection->Errors->GetItem(i);
            printf("\t Error number: %x\t%s", (LPCSTR) pErr->Number, 
                    (LPCSTR) pErr->Description);
        }
    }
}

///////////////////////////////////////////////////////////
//                                                       //
//      PrintComError Function                           //
//                                                       //
///////////////////////////////////////////////////////////

void PrintComError(_com_error &e)
{
    _bstr_t bstrSource(e.Source());
    _bstr_t bstrDescription(e.Description());

    // Print Com errors.  
    printf("\nError\n");
    printf("Code = %08lx\n", e.Error());
    printf("Code meaning = %s\n", e.ErrorMessage());
    printf("Source = %s\n", (LPCSTR) bstrSource);
    printf("Description = %s\n", (LPCSTR) bstrDescription);  
}