ADO大总结
ADO大总结
内容比较乱，作为草稿，对现有的ado数据库操作函数方法进行汇总。
小函数 m_pRecordset->RecordCount//取得记录数量
全局变量 #import "msado15.dll" no_namespace rename("EOF","adoEOF")rename("BOF","adoBOF") _ConnectionPtr m_pConnection; _RecordsetPtr m_pRecordset; 1.连接数据源OnInitADOConn(); //初始化OLE/COM库环境 ::CoInitialize(NULL); try{ //创建Connection对象 m_pCOnnection.CreateInstance("ADODB.Connection"); //设置连接字符串 _bstr_t strConnect="uid=;pwd=;DRIVER={Microsoft Access Driver(*mdb)};DBQ=database.mdb;"; m_pConnection->Open(strConnect,"","",adModeUnknown); } catch(_com_error e){ AfxMessageBox(e.Description); }
2.关闭数据库连接 if(m_pRecordset!=NULL) ?m_pRecordset->Close(); m_pConnection->Close(); ::CoUninitialize();//释放环境
3.获取记录集数据 传入一个_bstr_t bstrSQL (1)Open方法 try{ if(m_pConnection==NULL)//如果为空，重新连接 ?OnInitADOConn(); m_pRecordset.CreateInstance(__uuidof(Recordset)); m_pRecordset->Open(bstrSQL,m_pConnection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText); }//adCmdText：bstrSQL是文本.adCmdTable:bstrSQL是表名 (2)Execute方法 _RecordsetPtr Execute(_bstr_t CommandTex,VARIANT* RecordsAffeced,long Options) CommandText是SQL命令,RecordsAffeced是操作后影响的行数,Options是CommandText中内容的类型 Options:adCmdText文本,adCmdTable表名,adCmdStoredProc存储过程,adCmdUnknown类型未知 >>_variant_t RecordsAffected; try{ if(m_pConnection==NULL)//是否连接数据库 ?OnInitADOConn();//又重新连接 ?m_pConnection->Execute(bstrSQL,NULL,adCmdText); } catch(_com_error e) { e.Description(); return false; }
4.遍历记录集 MoveNext,MoveFirst,MoveLast,MovePrevious; (char *)(_bstr_t)m_pRecordset->GetCollect("姓名");//方法一 m_sName=(CStringW)(m_pAdoRecordset->Fields->Item[_variant_t("NAME")]->Value);//方法二 while(m_pRecordset->adoEOF==0) {m_pRecordset->MoveNext();} 5.添加数据 try{ m_pRecordset->AddNew();//开始添加 m_pRecordset->PutCollect("列名",(_bstr_t)m_id); m_pRecordset-->Update();//更新字段 } 6.修改数据 try{ m_pRecordset->Move((long)pos,vtMissing); m_pRecordset->PutCollect("姓名",(_bstr_t)m_name); m_pRecordset-->Update(); } 7.删除数据 m_pRecordset->Move((long)pos,vtMissing); m_pAdoRecordset->Delete(adAffectCurrent); m_pRecordset-->Update(); ??? try ??? { ?????? //假设删除第10条记录 ?????? m_pRecordset->MoveFirst();//注意一定要移到第一个 ?????? m_pRecordset->Move(9); ?????? m_pRecordset->Delete(adAffectCurrent); ?????? //参数adAffectCurrent为删除当前记录 ?????? m_pRecordset->Update(); ??? } ??? catch(_com_error *e) ??? { ?????? AfxMessageBox(e->ErrorMessage()); ??? } 8.保存图片（ 参考下一篇博客） ?char *m_pBuffer;//文件数据 ?DWORD m_filelen;//文件长度 ?VARIANT varblob; ?SAFEARRAY *psa; ?SAFEARRAYBOUND rgsabound[1]; ?rgsabound[0].lLbound=0; ?rgsabound[0].cElements=m_filelen; ?psa=SafeArrayCreate(VT_UI1,1,rgsabound); ?for(long i=0;i<(long)m_filelen;i++) ?{ ??SafeArrayPutElement(psa,&i,m_pBuffer++); ?} ?//记录值 ?varblob.vt=VT_ARRAY|VT_UI1; ?varblob.parray=psa; ?m_pRecordset->GetFields()->GetItem("PHOTO_DATA")->AppendChunk(varblob); ?m_pRecordset->Update(); 读取数据库语音数据 long lDataSize=m_pRecordset->GetFields()->GetItem("voice")->ActualSize;//取得数据区域大小 char *m_pBuffer; if(lDataSize>0) { //读取数据到varBLOB中 _variant_t varBLOB; varBLOB=m_pRecordse->GetFields()->GetItem("voice")->GetChunk(lDataSize); if(varBLOB.vt==(VT_ARRAY|VT_UI1)) ?{ ?if(m_pBuffer=new char[lDataSize+1]) ?{ ?char *pBuf=0; ?SafeArrayAccessData(varBLOB.parray,(void**)&pBuf); ?memcpy(m_pBuffer,pBuf,lDataSize);//赋值数据到m_pBuffer ?SafeArrayUnaccessData(varBLOB.parray); ?} ?} }
其他连接方法 打开 ?m_pAdoRecordset=NULL; ?m_pAdoConnect=NULL;//初始化 ?iCurrentOne=-1; ?//******************************************* ?if(FAILED(::CoInitialize(NULL)))//这句话很重要！ ?{ ??::AfxMessageBox(_T("fail to CInitialize(NULL)")); ??PostQuitMessage(-8);//? ?} ?HRESULT hr=m_pAdoConnect.CreateInstance(__uuidof(Connection)); ?if(FAILED(hr)){ ??::AfxMessageBox(_T("fail to create instance for _ConnectPtr")); ??PostQuitMessage(-8); ?} ?bstr_t strConnect="DSN=FRDB;\ ?????? DBQ=H:\\FRDB.accdb;\ ?????? DriverID=25;FIL=MS Access;MaxBufferSize=2048;PageTimeout=5;"; ?try{ ??m_pAdoConnect->Open(strConnect,"clc","",NULL); ?} ?catch(_com_error &e) ?{ ??::AfxMessageBox(e.Description()); ??PostQuitMessage(-8); ?} ?m_pAdoRecordset=NULL; ?hr=m_pAdoRecordset.CreateInstance(__uuidof(Recordset)); ?if(FAILED(hr)){ ??::AfxMessageBox(_T("fail to create instance for _RecordsetPtr")); ??PostQuitMessage(-8); ?} ?m_pAdoRecordset->Open(_variant_t("Person"),_variant_t((IDispatch*)
m_pAdoConnect,true),adOpenKeyset,adLockOptimistic,adCmdTable); 关闭 ?if(m_pAdoRecordset){?if(m_pAdoRecordset->State==adStateOpen){ ???m_pAdoRecordset->Close();?}} ?if(m_pAdoConnect) ?{?if(m_pAdoConnect->State==adStateOpen){ ???m_pAdoConnect->Close();}} ??::CoUninitialize();//关闭线程下的数据库 添加数据 m_pAdoRecordset->Fields->GetItem(_variant_t("NAME"))->Value=_variant_t(m_sName); 载入数据 m_sName=(CStringW)(m_pAdoRecordset->Fields->Item[_variant_t("NAME")]->Value);