哎呀媽呀！小伙伴們有沒有想過要用C語言去鏈接上數(shù)據(jù)庫呢？？？嘿嘿嘿，沒錯，就是OleDbConnection啦，那么今天蒟蒻我就來給大家整整這個操作吧！

首先，我們得知道什么是OleDbConnection？它可是一個能讓我們用C語言去鏈接各種數(shù)據(jù)庫的好東西嘞！它實現(xiàn)了OLE DB協(xié)議的一組類，允許以 OleDbCommand、OleDbDataAdaptor 和 OleDbDataReader 等方式使用 OLE DB 訪問數(shù)據(jù)庫，妙不可言吧！

好的，既然我們要使用OleDbConnection進行數(shù)據(jù)庫鏈接，那么我們得先開動手指打一下代碼了。（下面的代碼是針對Microsoft Access數(shù)據(jù)庫的，其他數(shù)據(jù)庫需要修改ConnectionString參數(shù)）

首先，我們需要引入相應(yīng)的頭文件：

#include

#include

#include

#include

#include

#include

#include

接下來，需要定義一些宏和變量，詳細的意思注釋如下：

#define BUFFER_LEN 64

#define TABLENAME _T("PersonInfo") //數(shù)據(jù)庫中的表名

#define STMTLEN 100

TCHAR szProvider[] = _T("Microsoft.Jet.OLEDB.4.0");

TCHAR szDataSource[] = _T("D:\\Data\\students.mdb"); //數(shù)據(jù)庫文件路徑

TCHAR szPersist[] = _T("Persist Security Info=False");

TCHAR szConnectString[BUFFER_LEN];

DBPROPIDSET rgPropSet[1];

DWORD dwStatus;

HRESULT hr;

IDBInitialize *pIDBInitialize = NULL;

IOpenRowset *pIOpenRowset = NULL;

IDBCreateSession *pIDBCreateSession;

ISessionProperties *pISessionProperties = NULL;

DBID dbidTable;

DBID dbidCol;

HACCESSOR hAccessor;

這里面涉及了一些重要的變量和宏的定義，要認真看喲！

然后，我們需要定義一個函數(shù)，這個函數(shù)是用來建立連接的，代碼如下：

HRESULT EstablishConnection()

{

HRESULT hr;

TCHAR strFilePath[MAX_PATH] = {0};

// 創(chuàng)建工作空間

hr = CoCreateInstance(CLSID_MSDAINITIALIZE, NULL, CLSCTX_INPROC_SERVER, IID_IDBInitialize, (LPVOID *)&pIDBInitialize);

if (FAILED(hr)) {

printf("Create workspace failed!\n");

return hr;

}

// 設(shè)置數(shù)據(jù)源的屬性

hr = pIDBInitialize -> Initialize();

if(FAILED(hr)) {

printf("Initialize() has failed!\n");

return hr;

}

// 獲取IDBCreateSession接口

hr = pIDBInitialize -> QueryInterface(

IID_IDBCreateSession,

(void**)&pIDBCreateSession

);

if (FAILED(hr)) {

printf("Query interface of IDBCreateSession fialed!\n");

return hr;

}

//建立連接的字符串

_stprintf_s(szConnectString, BUFFER_LEN, _T("Provider=%s;Data Source=%s;Jet OLEDB:Database Password=; %s"),szProvider, szDataSource, szPersist);

hr = pIDBCreateSession -> CreateSession(NULL, IID_ISessionProperties, (IUnknown **)&pISessionProperties);

if (FAILED(hr)) {

printf("CreateSession() failed!\n");

return hr;

}

//設(shè)置數(shù)據(jù)源屬性

hr = pISessionProperties -> SetProperty(DBPROPSET_DBINIT, DBPROP_AUTH_PERSIST_SENSITIVE_AUTHINFO, VARIANT_TRUE);

if (FAILED(hr)) {

printf("Set DBPROP_AUTH_PERSIST_SENSITIVE_AUTHINFO is failed!\n");

return hr;

}

hr = pISessionProperties -> SetProperty(DBPROPSET_DBINIT, DBPROP_INIT_PROMPT, (int)FALSE);

if (FAILED(hr)) {

printf("Set DBPROP_INIT_PROMPT is failed!\n");

return hr;

}

hr = pISessionProperties -> SetProperty(DBPROPSET_DBINIT, DBPROP_INIT_DATASOURCE, szDataSource);

if (FAILED(hr)) {

printf("Set DBPROP_INIT_DATASOURCE is failed!\n");

return hr;

}

hr = pISessionProperties -> SetProperty(DBPROPSET_DBINIT, DBPROP_INIT_PROVIDERSTRING, szConnectString);

if (FAILED(hr)) {

printf("Set DBPROP_INIT_PROVIDERSTRING is failed!\n");

return hr;

}

return hr;

}

這個函數(shù)是我們建立連接的核心所在，在調(diào)用此函數(shù)之前，需要先設(shè)置一些參數(shù)以及數(shù)據(jù)源的屬性等。

最后，我們再寫一個函數(shù)，來釋放資源，代碼如下：

void ReleaseResource()

{

if (hAccessor) {

pIOpenRowset ->ReleaseAccessor(hAccessor, NULL);

hAccessor = NULL;

}

if (pIOpenRowset) {

pIOpenRowset -> Release();

pIOpenRowset = NULL;

}

if (pIDBCreateSession) {

pIDBCreateSession -> Release();

pIDBCreateSession = NULL;

}

if (pIDBInitialize) {

pIDBInitialize -> Uninitialize();

pIDBInitialize -> Release();

pIDBInitialize = NULL;

}

if (pISessionProperties) {

pISessionProperties -> Release();

pISessionProperties = NULL;

}

}

那么，我們現(xiàn)在就可以愉快地使用OleDbConnection 來鏈接上我們的數(shù)據(jù)庫啦！下面給大家一個簡單的查詢的例子作為參考：

int main(void)

{

HRESULT hr;

IRowset *pIRowset = NULL;

HROW hRow;

HACCESSOR hAccessor;

ULONG ulTableType = 0;

DBBINDING dbBind[3];

BYTE buffer[1024] = {0};

TCHAR stmt[100] = _T("Select * from PersonInfo");

TCHAR tchName[100] = { 0 }, tchSex[100] = { 0 }, tchAge[5] = { 0 };

TCHAR strDataSource[MAX_PATH] = { 0 };

//建立連接

hr = EstablishConnection();

if (FAILED(hr)) {

printf("EstablishConnection() error!\n");

return -1;

}

//獲取IOpenRowset指針

hr = pIDBCreateSession -> GetDataSource(NULL, IID_IOpenRowset, (IUnknown **)&pIOpenRowset);

if (FAILED(hr)) {

printf("GetDataSource() failed!\n");

return -1;

}

//執(zhí)行查詢

hr = pIOpenRowset -> OpenRowset(NULL, &dbidTable, NULL, IID_IRowset, 0, NULL, (IUnknown **)&pIRowset);

if (FAILED(hr)) {

printf("OpenRowset() failed!\n");

return -1;

}

//為檢索結(jié)果創(chuàng)建訪問方法

hr = pIRowset -> GetNextRows(0, 0, 1, &ulTableType, &hRow);

if (FAILED(hr)) {

printf("GetNextRows() failed!\n");

return -1;

}

//設(shè)置訪問器

dbBind[0].iOrdinal = 1;

dbBind[0].wType = DBTYPE_WSTR;

dbBind[0].pTypeInfo= NULL;

dbBind[0].pBindExt = NULL;

dbBind[0].pObject = NULL;

dbBind[0].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;

dbBind[0].pVarData = NULL;

dbBind[0].obLength = 0;

dbBind[0].obStatus = 0;

dbBind[0].cbMaxLen = sizeof(tchName);

dbBind[0].obValue = 0;

dbBind[1].iOrdinal = 2;

dbBind[1].wType = DBTYPE_WSTR;

dbBind[1].pTypeInfo= NULL;

dbBind[1].pBindExt = NULL;

dbBind[1].pObject = NULL;

dbBind[1].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;

dbBind[1].pVarData = NULL;

dbBind[1].obLength = sizeof(tchName);

dbBind[1].obStatus = dbBind[1].obLength + dbBind[1].cbMaxLen;

dbBind[1].cbMaxLen = sizeof(tchSex);

dbBind[1].obValue = dbBind[1].obStatus + dbBind[1].cbMaxLen;

dbBind[2].iOrdinal = 3;

dbBind[2].wType = DBTYPE_WSTR;

dbBind[2].pTypeInfo= NULL;

dbBind[2].pBindExt = NULL;

dbBind[2].pObject = NULL;

dbBind[2].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;

dbBind[2].pVarData = NULL;

dbBind[2].obLength = sizeof(tchName) + sizeof(tchSex);

dbBind[2].obStatus = dbBind[2].obLength + dbBind[2].cbMaxLen;

dbBind[2].cbMaxLen = sizeof(tchAge);

dbBind[2].obValue = dbBind[2].obStatus + dbBind[2].cbMaxLen;

hr = pIRowset -> CreateAccessor(DBACCESSOR_ROWDATA, sizeof(dbBind)/sizeof(dbBind[0]), dbBind, 0, &hAccessor, NULL);

if (FAILED(hr)) {

printf("CreateAccessor() failed!\n");

return -1;

}

//檢索數(shù)據(jù)

while(hr != DB_S_ENDOFROWSET) {

hr = pIRowset -> GetData(hRow, hAccessor, buffer);

if (SUCCEEDED(hr)) {

tmemcpy(tchName, (TCHAR *)(buffer + dbBind[0].obValue), dbBind[0].cbMaxLen);

tmemcpy(tchSex , (TCHAR *)(buffer + dbBind[1].obValue), dbBind[1].cbMaxLen);

tmemcpy(tchAge , (TCHAR *)(buffer + dbBind[2].obValue), dbBind[2].cbMaxLen);

printf("%s\t%s\t%s\n", tchName, tchSex, tchAge);

}

}

//釋放資源

ReleaseResource();

system("pause");

return 0;

}

好啦，上面就是關(guān)于使用C語言連接OleDbConnection數(shù)據(jù)庫的全部操作步驟啦！在實際使用中，還是要多花時間多練習，熟能生巧嘛！ www.cppxvbw.com.cn 寧波海美seo網(wǎng)絡(luò)優(yōu)化公司 是網(wǎng)頁設(shè)計制作，網(wǎng)站優(yōu)化，企業(yè)關(guān)鍵詞排名，網(wǎng)絡(luò)營銷知識和開發(fā)愛好者的一站式目的地，提供豐富的信息、資源和工具來幫助用戶創(chuàng)建令人驚嘆的實用網(wǎng)站。 該平臺致力于提供實用、相關(guān)和最新的內(nèi)容，這使其成為初學者和經(jīng)驗豐富的專業(yè)人士的寶貴資源。