构建动态SQL查询

Question

我想从用户那里阅读value并在我的选择查询中使用它。如何在SQL查询中使用动态值？

我当前的代码给了我这个错误：

  

ORA-01002：提取失序

这是我的代码：

void buildQuery()
{
    cout << "Enter flight no :";
    cin >> value;
    strcpy((char *)sql_statement.arr,"select fname from flights where  
    flno = " + value );      
    cout << "Query is  " << (char *) sql_statement.arr<< endl;
}

void executeQuery()
{
    sql_statement.len = strlen((char *) sql_statement.arr);
    exec sql PREPARE S1 FROM :sql_statement;
    exec sql declare C1 cursor FOR S1;
    exec sql open C1  ;
    while(1)
    {
       exec sql FETCH C1 INTO :fname;
       if ( sqlca.sqlcode !=  0)
       {
          cout << "past fetch..." <<endl;
          break;
       }

    cout << "Employee Name is: = " << (char *)ename.arr << endl;
    }
  exec sql close C1;
}