發送短信 : Category hierarchy maintenance : a data-driven approach

 _____     _    _     _____     ______    ______  
|  __ \\  | || | ||  / ____||  /_   _//  /_____// 
| |  \ || | || | || / //---`'   -| ||-   `____ `  
| |__/ || | \\_/ || \ \\___     _| ||_   /___//   
|_____//   \____//   \_____||  /_____//  `__ `    
 -----`     `---`     `----`   `-----`   /_//     
                                         `-`