如何从oracle数据库c++中读取unicode

#include <iostream>
#include <sql.h>
#include <sqlext.h>

int main() {
    // Initialize ODBC environment
    SQLHENV env;
    SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &env);
    SQLSetEnvAttr(env, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0);

    // Connect to Oracle database
    SQLHDBC dbc;
    SQLAllocHandle(SQL_HANDLE_DBC, env, &dbc);
    SQLDriverConnect(dbc, NULL, (SQLCHAR*)"DRIVER={Oracle ODBC Driver};DBQ=your_database;UID=your_username;PWD=your_password;", SQL_NTS, NULL, 0, NULL, SQL_DRIVER_COMPLETE);

    // Execute SQL query
    SQLHSTMT stmt;
    SQLAllocHandle(SQL_HANDLE_STMT, dbc, &stmt);
    SQLExecDirect(stmt, (SQLCHAR*)"SELECT unicode_column FROM your_table", SQL_NTS);

    // Fetch and process results
    SQLWCHAR unicodeData[256];
    SQLLEN indicator;
    while (SQLFetch(stmt) == SQL_SUCCESS) {
        SQLGetData(stmt, 1, SQL_C_WCHAR, unicodeData, sizeof(unicodeData), &indicator);
        if (indicator != SQL_NULL_DATA) {
            std::wcout << unicodeData << std::endl;
        }
    }

    // Cleanup
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
    SQLDisconnect(dbc);
    SQLFreeHandle(SQL_HANDLE_DBC, dbc);
    SQLFreeHandle(SQL_HANDLE_ENV, env);

    return 0;
}