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C與Oracle數(shù)據(jù)庫更新操作一步搞定
準(zhǔn)備工作
1、安裝Oracle客戶端庫：在C程序中，需要使用Oracle提供的客戶端庫來連接和操作數(shù)據(jù)庫，可以從Oracle官方網(wǎng)站下載并安裝相應(yīng)的客戶端庫文件。
2、配置環(huán)境變量：將Oracle客戶端庫的路徑添加到系統(tǒng)的環(huán)境變量中，以便C程序能夠找到相關(guān)的頭文件和庫文件。
連接數(shù)據(jù)庫
1、包含頭文件：在C程序中，需要包含Oracle客戶端庫提供的頭文件，以獲取相關(guān)的函數(shù)聲明和數(shù)據(jù)結(jié)構(gòu)定義。
“`c
#include
#include
“`
2、初始化OCI環(huán)境：在使用OCI函數(shù)之前，需要先調(diào)用OCIInitialize()函數(shù)來初始化OCI環(huán)境。
“`c
err = OCIInitialize(NULL, NULL, NULL, NULL);
if (err != OCI_SUCCESS) {
printf("OCIInitialize failed: %s
", OCIErrorGetString(err));
return 1;
}
“`
3、連接數(shù)據(jù)庫：使用OCIHandleAlloc()函數(shù)分配一個連接句柄，并使用OCIHandleAlloc()函數(shù)分配一個語句句柄，使用OCISessionBegin()函數(shù)開始一個新的會話，并使用OCILogon()函數(shù)連接到數(shù)據(jù)庫。
“`c
OCIEnv *envhp;
OCIServer *srvhp;
OCIError *errhp;
OCISvcCtx *svchp;
OCISession *usrhp;
OCIStmt *stmthp;
OCIBind *bindhp;
ub4 mode;
const text *username = "your_username";
const text *password = "your_password";
const text *dbname = "your_database";
const text *service_name = "your_service_name";
const text *string_size = strlen(username) + 1;
const text *string_size2 = strlen(password) + 1;
const text *string_size3 = strlen(dbname) + 1;
const text *string_size4 = strlen(service_name) + 1;
errhp = (OCIError *)malloc(sizeof(OCIError));
srvhp = (OCIServer *)malloc(sizeof(OCIServer));
svchp = (OCISvcCtx *)malloc(sizeof(OCISvcCtx));
usrhp = (OCISession *)malloc(sizeof(OCISession));
stmthp = (OCIStmt *)malloc(sizeof(OCIStmt));
bindhp = (OCIBind *)malloc(sizeof(OCIBind));
mode = OCI_DEFAULT; //設(shè)置連接模式為默認(rèn)模式
err = OCIInitialize(errhp, (dvoid )0, (dvoid )0, (text *)0); //初始化OCI環(huán)境
if (err != OCI_SUCCESS) {
printf("OCIInitialize failed: %s
", OCIErrorGetString((dvoid *)errhp));
free(errhp);
free(srvhp);
free(svchp);
free(usrhp);
free(stmthp);
free(bindhp);
return 1;
}
err = OCIHandleAlloc((dvoid )&envhp, OCI_HTYPE_ENV, (dvoid )0); //分配環(huán)境句柄
if (err != OCI_SUCCESS) {
printf("OCIHandleAlloc failed: %s
", OCIErrorGetString((dvoid *)errhp));
OCILogoff(*usrhp, errhp); //注銷用戶會話并釋放資源
return 1;
}
err = OCIHandleAlloc((dvoid )&srvhp, OCI_HTYPE_SERVER, envhp, (dvoid )0); //分配服務(wù)器句柄
if (err != OCI_SUCCESS) {
printf("OCIHandleAlloc failed: %s
", OCIErrorGetString((dvoid *)errhp));
OCIHandleFree((dvoid *)envhp, OCI_HTYPE_ENV); //釋放環(huán)境句柄并退出程序
return 1;
}
err = OCIHandleAlloc((dvoid )&svchp, OCI_HTYPE_SVCCTX, envhp, (dvoid )0); //分配服務(wù)上下文句柄
if (err != OCI_SUCCESS) {
printf("OCIHandleAlloc failed: %s
", OCIErrorGetString((dvoid *)errhp));
OCIHandleFree((dvoid *)srvhp, OCI_HTYPE_SERVER); //釋放服務(wù)器句柄并退出程序
return 1;
}
err = OCIHandleAlloc((dvoid )&usrhp, OCI_HTYPE_SESSION, envhp, (dvoid )0); //分配用戶會話句柄并開始新的會話
if (err != OCI_SUCCESS) {
printf("OCIHandleAlloc failed: %s
", OCIErrorGetString((dvoid *)errhp));
OCIHandleFree((dvoid *)svchp, OCI_HTYPE_SVCCTX); //釋放服務(wù)上下文句柄并退出程序
return 1;
}
//設(shè)置用戶名、密碼、數(shù)據(jù)庫名和服務(wù)名等連接參數(shù)，并進(jìn)行登錄操作…（省略）…
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