c语言编程在Oracle平台上的实践经验（c oracle 编译）

C语言编程在Oracle平台上的实践经验

随着大数据和云计算的兴起，Oracle作为一种关系型数据库管理系统，已经被广泛应用于企业级应用程序的开发中。在这样一个背景下，将C语言编程应用于Oracle平台上的开发，可以充分利用其优秀的性能和高效的内存管理能力，实现更加安全和可靠的数据库开发和管理。本文将就此为您介绍一些C语言编程在Oracle平台上的实践经验。

一、连接Oracle数据库

在C语言中连接Oracle数据库，我们可以使用OCI (Oracle Call Interface)来实现。OCI提供了一组API，用于协作Oracle数据库。使用OCI编写代码时，我们必须包含Oracle提供的头文件oci.h，并且链接Oracle库文件libclntsh.x.x.x.x.x。下面是一个简单的示例代码，演示了如何用C语言连接Oracle数据库：

“`c

#include

#include

#include

int mn(int argc, char *argv[]) {

OCIEnv *envhp;

OCIError *errhp;

OCIServer *srvhp;

OCISession *svchp;

OTS *authp;

sword status, major, minor, errcode;

if (OCIEnvCreate(&envhp, OCI_THREADED | OCI_OBJECT, NULL, NULL, NULL, NULL, 0, NULL)) {

printf(“OCIEnvCreate fled!\n”);

exit(1);

}

if (OCIHandleAlloc(envhp, (void **)&errhp, OCI_HTYPE_ERROR, 0, NULL)) {

printf(“OCIHandleAlloc for errhp fled!\n”);

exit(1);

}

if (OCIHandleAlloc(envhp, (void **)&srvhp, OCI_HTYPE_SERVER, 0, NULL)) {

printf(“OCIHandleAlloc for srvhp fled!\n”);

exit(1);

}

if (OCIHandleAlloc(envhp, (void **)&authp, OCI_HTYPE_SESSION, 0, NULL)) {

printf(“OCIHandleAlloc for authp fled!\n”);

exit(1);

}

if (OCILogon2(envhp, errhp, &srvhp, strlen(“username”), “username”, strlen(“password”), “password”, strlen(“tnsname”), “tnsname”, OCI_DEFAULT)) {

printf(“OCILogon2 fled!\n”);

OCIErrorGet(errhp, 1, NULL, &errcode, (OraText *)NULL, 0, OCI_HTYPE_ERROR);

printf(“Error code : %d”, errcode);

exit(1);

}

if (OCIHandleAlloc(envhp, (void **)&svchp, OCI_HTYPE_SESSION, 0, NULL)) {

printf(“OCIHandleAlloc for svchp fled!\n”);

exit(1);

}

if (OCIAttrSet(authp, OCI_HTYPE_SESSION, (void *)srvhp, 0, OCI_ATTR_SERVER, errhp)) {

printf(“OCIAttrSet for OCI_ATTR_SERVER fled!\n”);

exit(1);

}

if (OCIAttrSet(authp, OCI_HTYPE_SESSION, “username”, strlen(“username”), OCI_ATTR_USERNAME, errhp)) {

printf(“OCIAttrSet for OCI_ATTR_USERNAME fled!\n”);

exit(1);

}

if (OCIAttrSet(authp, OCI_HTYPE_SESSION, “password”, strlen(“password”), OCI_ATTR_PASSWORD, errhp)) {

printf(“OCIAttrSet for OCI_ATTR_PASSWORD fled!\n”);

exit(1);

}

if (OCISessionBegin(envhp, errhp, svchp, (ub4) OCI_CRED_RDBMS, (ub4) OCI_DEFAULT)) {

printf(“OCISessionBegin fled!\n”);

OCIErrorGet(errhp, 1, NULL, &errcode, (OraText *)NULL, 0, OCI_HTYPE_ERROR);

printf(“Error code : %d”, errcode);

exit(1);

}

printf(“Connected!\n”);

if (OCISessionEnd(envhp, errhp, svchp, OCI_DEFAULT)) {

printf(“OCISessionEnd fled!\n”);

exit(1);

}

if (OCIHandleFree(srvhp, OCI_HTYPE_SERVER)) {

printf(“OCIHandleFree for srvhp fled!\n”);

exit(1);

}

if (OCIHandleFree(svchp, OCI_HTYPE_SESSION)) {

printf(“OCIHandleFree for svchp fled!\n”);

exit(1);

}

if (OCIHandleFree(authp, OCI_HTYPE_SESSION)) {

printf(“OCIHandleFree for authp fled!\n”);

exit(1);

}

if (OCIHandleFree(errhp, OCI_HTYPE_ERROR)) {

printf(“OCIHandleFree for errhp fled!\n”);

exit(1);

}

if (OCIEnvDestroy(envhp)) {

printf(“OCIEnvDestroy fled!\n”);

exit(1);

}

printf(“Disconnected!\n”);

return 0;

}

上述代码中，我们在OCIEnvCreate函数中创建了一个OCI的环境句柄envhp，随后使用OCIHandleAlloc分配了用于处理错误的OCIError句柄errhp、用于连接服务器的OCIServer句柄srvhp、以及用于授权的OCISession句柄svchp。在OCILogon2函数中，我们使用OCI_DEFAULT作为参数打开了一个会话，并在OCISessionBegin函数中启动了一个会话。在会话结束后，我们使用OCIHandleFree分别释放了OCIServer、OCISession、OCIError句柄，最后调用OCIEnvDestroy函数销毁了OCI环境句柄。

二、执行SQL语句

OCI提供了OCIStmtPrepare、OCIStmtExecute、OCIStmtFetch等函数，用于执行SQL语句。其中，OCIStmtPrepare函数用于准备SQL语句，OCIStmtExecute函数用于执行SQL语句，OCIStmtFetch函数用于从游标中获取查询结果。

下面是一个简单的示例代码，演示了如何用C语言执行SQL语句：

```c
#include 
#include 
#include 
int mn(int argc, char *argv[]) {
    OCIEnv *envhp;
    OCIError *errhp;
    OCIServer *srvhp;
    OCISession *svchp;
    OTS *authp;
    OCIStmt *stmthp;
    OCIDefine *defhp;
    sword status, major, minor, errcode;
    int empno, sal;
    if (OCIEnvCreate(&envhp, OCI_THREADED | OCI_OBJECT, NULL, NULL, NULL, NULL, 0, NULL)) {
        printf("OCIEnvCreate fled!\n");
        exit(1);
    }
    if (OCIHandleAlloc(envhp, (void **)&errhp, OCI_HTYPE_ERROR, 0, NULL)) {
        printf("OCIHandleAlloc for errhp fled!\n");
        exit(1);
    }
    if (OCIHandleAlloc(envhp, (void **)&srvhp, OCI_HTYPE_SERVER, 0, NULL)) {
        printf("OCIHandleAlloc for srvhp fled!\n");
        exit(1);
    }
    if (OCIHandleAlloc(envhp, (void **)&authp, OCI_HTYPE_SESSION, 0, NULL)) {
        printf("OCIHandleAlloc for authp fled!\n");
        exit(1);
    }
    if (OCILogon2(envhp, errhp, &srvhp, strlen("username"), "username", strlen("password"), "password", strlen("tnsname"), "tnsname", OCI_DEFAULT)) {
        printf("OCILogon2 fled!\n");
        OCIErrorGet(errhp, 1, NULL, &errcode, (OraText *)NULL, 0, OCI_HTYPE_ERROR);
        printf("Error code : %d", errcode);
        exit(1);
    }
    if (OCIHandleAlloc(envhp, (void **)&svchp, OCI_HTYPE_SESSION, 0, NULL)) {
        printf("OCIHandleAlloc for svchp fled!\n");
        exit(1);
    }
    if (OCIAttrSet(authp, OCI_HTYPE_SESSION, (void *)srvhp, 0, OCI_ATTR_SERVER, errhp)) {
        printf("OCIAttrSet for OCI_ATTR_SERVER fled!\n");
        exit(1);
    }
    if (OCIAttrSet(authp, OCI_HTYPE_SESSION, "username", strlen("username"), OCI_ATTR_USERNAME, errhp)) {
        printf("OCIAttrSet for OCI_ATTR_USERNAME fled!\n");
        exit(1);
    }
    if (OCIAttrSet(authp, OCI_HTYPE_SESSION, "password", strlen("password"), OCI_ATTR_PASSWORD, errhp)) {
        printf("OCIAttrSet for OCI_ATTR_PASSWORD fled!\n");
        exit(1);
    }
    if (OCISessionBegin(envhp,