在C++中處理Oracle數據庫異常，你需要使用Oracle Call Interface (OCI)庫

1. 包含必要的頭文件：

#include<iostream>
#include <oci.h>

2. 定義一個宏來檢查OCI函數調用是否成功，并在發生錯誤時拋出異常：

#define CHECK_OCI(func, envhp, errhp) \
    if ((func) != OCI_SUCCESS) { \
        throw OracleException(envhp, errhp); \
    }

3. 創建一個自定義異常類OracleException，用于處理Oracle數據庫異常：

class OracleException : public std::exception {
public:
    OracleException(OCIEnv* envhp, OCIError* errhp) {
        OCIErrorGet((dvoid*)errhp, 1, NULL, &errorCode, errorMessage, sizeof(errorMessage), OCI_HTYPE_ERROR);
        OCIHandleFree((dvoid*)envhp, OCI_HTYPE_ENV);
        OCIHandleFree((dvoid*)errhp, OCI_HTYPE_ERROR);
    }

    const char* what() const noexcept override {
        return errorMessage;
    }

    int getErrorCode() const {
        return errorCode;
    }

private:
    char errorMessage[512];
    int errorCode;
};

4. 在你的程序中使用這些宏和異常處理類來處理Oracle數據庫異常。例如，連接到數據庫：

int main() {
    try {
        OCIEnv* envhp = nullptr;
        OCIError* errhp = nullptr;
        OCISvcCtx* svchp = nullptr;
        OCIServer* srvhp = nullptr;
        OCISession* usrhp = nullptr;

        // 初始化環境句柄
        CHECK_OCI(OCIEnvCreate(&envhp, OCI_DEFAULT, 0, 0, 0, 0, 0, 0), envhp, errhp);

        // 分配錯誤句柄
        CHECK_OCI(OCIHandleAlloc((dvoid*)envhp, (dvoid**)&errhp, OCI_HTYPE_ERROR, 0, 0), envhp, errhp);

        // 分配服務器句柄
        CHECK_OCI(OCIHandleAlloc((dvoid*)envhp, (dvoid**)&srvhp, OCI_HTYPE_SERVER, 0, 0), envhp, errhp);

        // 分配服務上下文句柄
        CHECK_OCI(OCIHandleAlloc((dvoid*)envhp, (dvoid**)&svchp, OCI_HTYPE_SVCCTX, 0, 0), envhp, errhp);

        // 分配會話句柄
        CHECK_OCI(OCIHandleAlloc((dvoid*)envhp, (dvoid**)&usrhp, OCI_HTYPE_SESSION, 0, 0), envhp, errhp);

        // 設置用戶名和密碼
        CHECK_OCI(OCIAttrSet((dvoid*)usrhp, OCI_HTYPE_SESSION, (dvoid*)"username", (ub4)strlen("username"), OCI_ATTR_USERNAME, errhp), envhp, errhp);
        CHECK_OCI(OCIAttrSet((dvoid*)usrhp, OCI_HTYPE_SESSION, (dvoid*)"password", (ub4)strlen("password"), OCI_ATTR_PASSWORD, errhp), envhp, errhp);

        // 連接到數據庫
        CHECK_OCI(OCIServerAttach(srvhp, errhp, (text*)"//localhost:1521/orcl", (ub4)strlen("//localhost:1521/orcl"), 0), envhp, errhp);
        CHECK_OCI(OCIAttrSet((dvoid*)svchp, OCI_HTYPE_SVCCTX, (dvoid*)srvhp, 0, OCI_ATTR_SERVER, errhp), envhp, errhp);
        CHECK_OCI(OCISessionBegin(svchp, errhp, usrhp, OCI_CRED_RDBMS, OCI_DEFAULT), envhp, errhp);
        CHECK_OCI(OCIAttrSet((dvoid*)svchp, OCI_HTYPE_SVCCTX, (dvoid*)usrhp, 0, OCI_ATTR_SESSION, errhp), envhp, errhp);

        // 在此處執行其他數據庫操作...

        // 斷開連接
        CHECK_OCI(OCISessionEnd(svchp, errhp, usrhp, OCI_DEFAULT), envhp, errhp);
        CHECK_OCI(OCIServerDetach(srvhp, errhp, OCI_DEFAULT), envhp, errhp);

        // 釋放句柄
        OCIHandleFree((dvoid*)usrhp, OCI_HTYPE_SESSION);
        OCIHandleFree((dvoid*)svchp, OCI_HTYPE_SVCCTX);
        OCIHandleFree((dvoid*)srvhp, OCI_HTYPE_SERVER);
        OCIHandleFree((dvoid*)errhp, OCI_HTYPE_ERROR);
        OCIHandleFree((dvoid*)envhp, OCI_HTYPE_ENV);
    } catch (const OracleException& e) {
        std::cerr << "Oracle Error: " << e.what() << " (Error Code: " << e.getErrorCode() << ")"<< std::endl;
        return 1;
    }

    return 0;
}

這樣，當OCI函數調用失敗時，程序將拋出一個OracleException異常，你可以捕獲該異常并處理錯誤。