/* 定義全局變量 */
OCIEnv          *envhp = NULL;          /* 環境句柄指針 */
OCIError        *errhp = NULL;          /* 錯誤句柄指針 */
OCIServer       *svrhp = NULL;          /* 服務器句柄指針 */
OCISession      *usrhp = NULL;          /* 用戶會話句柄指針 */
OCISvcCtx       *svchp = NULL;          /* 服務上下文句柄指針 */
/*
 * Oralce數據庫ip地址為192.168.10.110，端口為1521，服務名為orcl
 * 數據庫用戶名為scott，密碼為tigger
 * 以上面的信息為例，連接到數據庫
 */int connect_oracle(void){
    sword       rc;
    char        user[32];
    char        passwd[32];
    char        dblink[256];

    /* 創建環境句柄 */
    rc = OCIEnvCreate(
        &envhp,
        OCI_DEFAULT,
        (void *)NULL,
        NULL,
        NULL,
        NULL,
        (size_t)0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIEnvCreate() - allocate OCI env handle error !\n");
        return (-1);
    }

    /* 分配錯誤句柄 */
    rc = OCIHandleAlloc(
        (void *)envhp,
        (void **)&errhp,
        OCI_HTYPE_ERROR,
        0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleAlloc() - allocate OCI error handle error !\n");
        return (-1);
    }

    /* 分配服務器句柄 */
    rc = OCIHandleAlloc(
        (void *)envhp,
        (void **)&svrhp,
        OCI_HTYPE_SERVER,
        0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleAlloc() - allocate server handle error !\n");
        return (-1);
    }

    strcpy(dblink, "//192.168.10.110:1521/orcl");

    /* 建立到Oracle數據庫的通信路徑 */
    rc = OCIServerAttach(
        svrhp,
        errhp,
        (const OraText *)dblink,
        strlen(dblink),
        OCI_DEFAULT
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIServerAttach() - establish an access path error !\n");
        return (-1);
    }

    /* 分配服務上下文句柄 */
    rc = OCIHandleAlloc(
        (void *)envhp,
        (void **)&svchp,
        OCI_HTYPE_SVCCTX,
        0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleAlloc() - allocate service context error !\n");
        return (-1);
    }

    /* 把服務器句柄放入服務上下文句柄的屬性中 */
    rc = OCIAttrSet(
        (void *)svchp,
        OCI_HTYPE_SVCCTX,
        (void *)svrhp,
        0,
        OCI_ATTR_SERVER,
        errhp
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "Set server attribute error !\n");
        return (-1);
    }

    /* 分配用戶會話句柄 */
    rc = OCIHandleAlloc(
        (void *)envhp,
        (void **)&usrhp,
        OCI_HTYPE_SESSION,
        0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleAlloc() - allocate session handle error !\n");
        return (-1);
    }

    strcpy(user, "scott");

    /* 設置認證用戶屬性 */
    rc = OCIAttrSet(
        (void *)usrhp,
        OCI_HTYPE_SESSION,
        (void *)user,
        strlen(user),
        OCI_ATTR_USERNAME,
        errhp
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "Set user attribute error !\n");
        return (-1);
    }

    strcpy(passwd, "tigger");

    /* 設置認證密碼屬性 */
    rc = OCIAttrSet(
        (void *)usrhp,
        OCI_HTYPE_SESSION,
        (void *)passwd,
        strlen(passwd),
        OCI_ATTR_PASSWORD,
        errhp
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "Set password attribute error !\n");
        return (-1);
    }

    /* 開啟一個用戶會話 */
    rc = OCISessionBegin(
        svchp,
        errhp,
        usrhp,
        OCI_CRED_RDBMS,
        OCI_DEFAULT
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCISessionBegin() - establish user session error !\n");
        return (-1);
    }

    /* 把用戶會話句柄放入服務上下文句柄屬性中 */
    rc = OCIAttrSet(
        (void *)svchp,
        OCI_HTYPE_SVCCTX,
        (void *)usrhp,
        0,
        OCI_ATTR_SESSION,
        errhp
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "Set user session attribute error !\n");
        return (-1);
    }

    return (0);
}