如何在C++中处理Oracle数据库异常

在C++中处理Oracle数据库异常，你需要使用Oracle Call Interface (OCI)库

包含必要的头文件：

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

定义一个宏来检查OCI函数调用是否成功，并在发生错误时抛出异常：

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

创建一个自定义异常类OracleException，用于处理Oracle数据库异常：

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;
};

在你的程序中使用这些宏和异常处理类来处理Oracle数据库异常。例如，连接到数据库：

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

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

        // 分配错误句柄
        CHECK_OCI(OCIHandleAlloc((dvoid*)envhp, (dvoid**)&errhp, OCI_HTYPE_ERROR, 0, 0), envhp, errhp);

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

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

        // 分配会话句柄
        CHECK_OCI(OCIHandleAlloc((dvoid*)envhp, (dvoid**)&usrhp, OCI_HTYPE_SESSION, 0, 0), envhp, errhp);

        // 设置用户名和密码
        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);

        // 连接到数据库
        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);

        // 在此处执行其他数据库操作...

        // 断开连接
        CHECK_OCI(OCISessionEnd(svchp, errhp, usrhp, OCI_DEFAULT), envhp, errhp);
        CHECK_OCI(OCIServerDetach(srvhp, errhp, OCI_DEFAULT), envhp, errhp);

        // 释放句柄
        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;
}

这样，当OCI函数调用失败时，程序将抛出一个OracleException异常，你可以捕获该异常并处理错误。

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