本文主要是介绍数据源的三种访问方式，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
数据源的三种访问方式：
1、使用OLEDB数据库连接对话框 链接到数据源
2、使用纯代码方式连接到指定的数据源
3、使用连接字符串得到一个IDBInitialize接口
代码：
#include <tchar.h>
#include <windows.h>
#include <strsafe.h>#define COM_NO_WINDOWS_H //如果已经包含了Windows.h或不使用其他Windows库函数时
#define DBINITCONSTANTS
#define INITGUID
#define OLEDBVER 0x0260
#include <oledb.h>
#include <oledberr.h>
#include <msdasc.h>#define GRS_ALLOC(sz) HeapAlloc(GetProcessHeap(),0,sz)
#define GRS_CALLOC(sz) HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,sz)
#define GRS_SAFEFREE(p) if(NULL != p){HeapFree(GetProcessHeap(),0,p);p=NULL;}#define GRS_USEPRINTF() TCHAR pBuf[1024] = {}
#define GRS_PRINTF(...) \StringCchPrintf(pBuf,1024,__VA_ARGS__);\WriteConsole(GetStdHandle(STD_OUTPUT_HANDLE),pBuf,lstrlen(pBuf),NULL,NULL);#define GRS_SAFERELEASE(I) if(NULL != I){I->Release();I=NULL;}
#define GRS_COM_CHECK(hr,...) if(FAILED(hr)){GRS_PRINTF(__VA_ARGS__);goto CLEAR_UP;}#define GRS_DEF_INTERFACE(i) i* p##i = NULL;
#define GRS_QUERYINTERFACE(i,iid) \if(FAILED(hr = (i)->QueryInterface(IID_##iid, (void **)&p##iid)) )\{\GRS_PRINTF(_T("不支持'%s'接口\n"),_T(#iid));\}\else\{\GRS_PRINTF(_T("支持'%s'接口\n"),_T(#iid));\}\GRS_SAFERELEASE(p##iid);//FAILED(hr = CLSIDFromProgID(L"SQLOLEDB", &clsid) )int _tmain()
{GRS_USEPRINTF();CoInitialize(NULL);//初始化COM组件IDBPromptInitialize* pIDBPromptInitialize =NULL;IDataInitialize* pIDataInitialize =NULL;LPOLESTR pLinkString =NULL;//以下是IDBInitialize接口的等价接口定义//1必须支持的接口GRS_DEF_INTERFACE(IDBInitialize);GRS_DEF_INTERFACE(IDBCreateSession);GRS_DEF_INTERFACE(IDBProperties);GRS_DEF_INTERFACE(IPersist);//2可选择支持的GRS_DEF_INTERFACE(IConnectionPointContainer);GRS_DEF_INTERFACE(IDBAsynchStatus);GRS_DEF_INTERFACE(IDBDataSourceAdmin);GRS_DEF_INTERFACE(IDBInfo);GRS_DEF_INTERFACE(IPersistFile);GRS_DEF_INTERFACE(ISupportErrorInfo);HWND hWndParent=GetDesktopWindow();CLSID clsid={};//1使用OLEDB数据库连接对话框链接到数据源HRESULT hr=CoCreateInstance(CLSID_DataLinks,NULL,CLSCTX_INPROC_SERVER,IID_IDBPromptInitialize,(void**)&pIDBPromptInitialize);//下面这句话弹出数据库连接对话框hr=pIDBPromptInitialize->PromptDataSource(NULL,hWndParent, //DBPROMPTOPTIONS_PROPERTYSHEET,0,NULL,NULL,IID_IDBInitialize,(IUnknown**)&pIDBInitialize);hr=pIDBPromptInitialize->QueryInterface(IID_IDataInitialize,(void**)&pIDataInitialize);hr=pIDataInitialize->GetInitializationString(pIDBInitialize,TRUE,&pLinkString);hr=pIDBInitialize->Initialize();//测试都支持哪些接口/*GRS_QUERYINTERFACE(pIDBInitialize,IDBCreateSession);GRS_QUERYINTERFACE(pIDBInitialize,IDBProperties);GRS_QUERYINTERFACE(pIDBInitialize,IPersist);GRS_QUERYINTERFACE(pIDBInitialize,IConnectionPointContainer);GRS_QUERYINTERFACE(pIDBInitialize,IDBAsynchStatus);GRS_QUERYINTERFACE(pIDBInitialize,IDBDataSourceAdmin);GRS_QUERYINTERFACE(pIDBInitialize,IDBInfo);GRS_QUERYINTERFACE(pIDBInitialize,IPersistFile);GRS_QUERYINTERFACE(pIDBInitialize,ISupportErrorInfo);
*///断开数据库连接
pIDBInitialize->Uninitialize();
GRS_SAFERELEASE(pIDBInitialize);
GRS_SAFERELEASE(pIDBPromptInitialize);//2使用纯代码方式链接到指定的数据源
hr=CoCreateInstance( CLSID_MSDAINITIALIZE,NULL,CLSCTX_INPROC_SERVER,IID_IDataInitialize,(void**)&pIDataInitialize);
hr=CLSIDFromProgID(_T("SQLOLEDB"),&clsid);
//创建数据源链接对象和初始化接口
hr=pIDataInitialize->CreateDBInstance( clsid,NULL,CLSCTX_INPROC_SERVER,NULL,IID_IDBInitialize,(IUnknown**)&pIDBInitialize);
//准备连接属性
//虽然后面只有4个属性，但是仍然要定义和初始化4+1个属性
DBPROP InitProperties[5]={};
DBPROPSET rgInitPropSet[1]={};//指定数据库实例名
InitProperties[0].dwPropertyID =DBPROP_INIT_DATASOURCE;
InitProperties[0].vValue.vt =VT_BSTR;
InitProperties[0].vValue.bstrVal =SysAllocString(L"YuZhiBo-PC");
InitProperties[0].dwOptions =DBPROPOPTIONS_REQUIRED;
InitProperties[0].colid =DB_NULLID;//指定数据库名
InitProperties[1].dwPropertyID =DBPROP_INIT_CATALOG;
InitProperties[1].vValue.vt =VT_BSTR;
InitProperties[1].vValue.bstrVal =SysAllocString(L"scott");
InitProperties[1].dwOptions =DBPROPOPTIONS_REQUIRED;
InitProperties[1].colid =DB_NULLID;// user ID
InitProperties[2].dwPropertyID =DBPROP_AUTH_USERID;
InitProperties[2].vValue.vt =VT_BSTR;
InitProperties[2].vValue.bstrVal =SysAllocString(OLESTR("sa"));//password
InitProperties[3].dwPropertyID =DBPROP_AUTH_PASSWORD;
InitProperties[3].vValue.vt =VT_BSTR;
InitProperties[3].vValue.bstrVal =SysAllocString(OLESTR("tiger"));//创建一个GUID为DBPROPSET_DBINIT的属性集合，这样是初始化链接是需要的唯一一个属性集合
rgInitPropSet[0].guidPropertySet=DBPROPSET_DBINIT;
rgInitPropSet[0].cProperties=4;
rgInitPropSet[0].rgProperties=InitProperties;//得到数据库初始化的属性接口
hr=pIDBInitialize->QueryInterface(IID_IDBProperties,(void**)&pIDBProperties);
GRS_COM_CHECK(hr,_T("获取IDBProperties接口失败，错误码：0x%08\n"),hr);
hr=pIDBProperties->SetProperties(1,rgInitPropSet);
GRS_COM_CHECK(hr,_T("设置链接属性失败，错误码:0x%08\n"),hr);//属性一旦完成，相应的接口就可以释放了
GRS_SAFERELEASE(pIDBProperties);//根据指定的属性链接到数据库
hr=pIDBInitialize->Initialize();
GRS_COM_CHECK(hr,_T("使用属性链接到数据源失败，错误码:0x%08x\n"),hr);
GRS_PRINTF(_T("使用属性集方式链接到数据源成功！\n"));pIDBInitialize->Uninitialize();
GRS_SAFERELEASE(pIDBInitialize);//3使用链接字符串得到一个IDBInitialize接口
hr=pIDataInitialize->GetDataSource( NULL,CLSCTX_INPROC_SERVER, //class context in process serverL"Provider=SQLOLEDB.1;Persist Security info=False;User ID=sa;Password=tiger;Initial Catalog=scott; Data Source=YuZhiBo-PC;",__uuidof(IDBInitialize),(IUnknown**)&pIDBInitialize);
GRS_COM_CHECK(hr,_T("使用连接字符串获取数据源接口IDBInitialize失败"));
//链接到数据库
hr=pIDBInitialize->Initialize();
GRS_COM_CHECK(hr,_T("使用连接字符串链接数据源失败。\n"));
GRS_PRINTF(_T("使用字符串连接到数据源成功！\n"));CLEAR_UP:if(NULL != pIDBInitialize){pIDBInitialize->Uninitialize();}GRS_SAFERELEASE(pIDBProperties);GRS_SAFERELEASE(pIDataInitialize);GRS_SAFERELEASE(pIDBInitialize);GRS_SAFERELEASE(pIDBPromptInitialize);_tsystem(_T("PAUSE"));CoUninitialize();return 0;
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