ADO经典例子

深藏阁楼爱情的钟 2022-01-24 00:07 209阅读 0赞

//数据库操作最好用try和catch
    try
    {
    }
    catch (_com_error &e)
    {
        AfxMessageBox(_T("Initiate failed!"));
        cout<<e.Description()<<endl;
    }
    
    //添加动态库
    #import "C:\Program Files\Common Files\System\ado\msado15.dll" no_namespace rename("EOF","adoEOF") rename("BOF","adoBOF")
    
    //bu'zh由于ADO库是一个com动态库，因此在应用程序调用ADO之前，必须初始化com环境。
    ::CoInitialize(NULL); //初始化COM环境
    
    _ConnectionPtr pMyConnect(__uuidof(Connection));//定义连接对象并实例化对象
    _RecordsetPtr pRst(__uuidof(Recordset));//定义记录集对象并实例化对象
    //步骤2：创建数据源连接
    CString ConnectionString = _T("");
    ConnectionString.Format(_T("Provider=OraOLEDB.Oracle;Data Source=%s;User Id=%s;Password=%s;"),m_sSQLName1,m_sUserName1,m_sPassword1);
    pMyConnect->Open(_bstr_t(ConnectionString),"","",adModeUnknown);//打开链接
    
    //步骤3：对数据源中的数据库/表进行操作
    //打开结果集
    //pRst->Open("select * from DJ_NSRXX",_variant_t((IDispatch*)pMyConnect,true),adOpenStatic,adLockOptimistic,adCmdText);
    pRst = pMyConnect->Execute("select * from DJ_NSRXX",NULL,adCmdText);
    if(!pRst->adoBOF)
    {
        pRst->MoveFirst();
    }
    else
    {
        cout<<"Data is empty!"<<endl;
        return ;
    }
    vector<_bstr_t> column_name;
    
    /*存储表的所有列名，显示表的列名*/
    for(int i=0; i< pRst->Fields->GetCount();i++)
    {
        //cout<<pRst->Fields->GetItem(_variant_t((long)i))->Name<<" ";
        //AfxMessageBox(pRst->Fields->GetItem(_variant_t((long)i))->Name);
        column_name.push_back(pRst->Fields->GetItem(_variant_t((long)i))->Name);
    }
    cout<<endl;
    
    /*对表进行遍历访问,显示表中每一行的内容*/
    while(!pRst->adoEOF)
    {
        vector<_bstr_t>::iterator iter=column_name.begin();
        for(iter;iter!=column_name.end();iter++)
        {
            if(pRst->GetCollect(*iter).vt !=VT_NULL)
            {
                cout<<(_bstr_t)pRst->GetCollect(*iter)<<" ";
                AfxMessageBox((_bstr_t)pRst->GetCollect(*iter));
            }
            else
            {
                cout<<"NULL"<<endl;
            }
        }
        pRst->MoveNext();
        cout<<endl;
    }
    
    //步骤4：关闭数据源
    /*关闭数据库并释放指针*/
    pRst->Close();     //关闭记录集
    pMyConnect->Close();//关闭数据库
    pRst.Release();//释放记录集对象指针
    pMyConnect.Release();//释放连接对象指针
    
    ::CoUninitialize(); //在程序最后还要释放com环境
    
    //取数据和写数据操作
    while(!pRst->adoEOF)
    {
        pRst2->AddNew();
        int nLength = 56;
        for(int i=0;i<nLength;i++)
        {
            CString FieldName = arrayFields2[i];
            if(pRst->GetCollect((_variant_t)FieldName).vt != VT_NULL)
            {
                CString str1 = (_bstr_t)pRst->GetCollect((_variant_t)FieldName);
                pRst2->PutCollect((LPCTSTR)FieldName,(_variant_t)str1);
            }
        }
        pRst2->Update();
        pRst->MoveNext();
    }