[[alternative]]A Study of Resolving Data Synchronization Problems between Mobile Device and Server under Poor Network Environment

[[abstract]]目前行動裝置的應用與日俱增，其中不乏對行動裝置資料庫操作的系統，但因環境及網路等因素，行動裝置與伺服器的資料庫間存在資料同步的問題。研究上卻無一套能完整適用於Web Apps的資料同步模組及產品，因此，本研究以長期照顧為例，解決建置行動裝置應用系統時的資料同步問題。系統可針對使用者所需之表單資料預載至行動裝置上，在離線狀態時能對表單資料進行新增、修改、刪除，於連線狀態時再將受影響的資料自動回存至伺服器資料庫。本研究之研究架構主要分資料預載模組及資料回存模組，其中資料預載模組主要負責下載並更新符合使用者權限及任務所需之資料至行動裝置上，且於連線狀態時檢查資料的完整性，以達成離線使用之目的及提升系統使用之效能；資料回存模組主要負責記錄使用者於系統使用期間之任何資料修改歷程，並於有網路的狀態時蒐集所有受影響之資料，再以表單為單位自動進行上傳。本研究分析出資料預載及回存所需之資料表，包括伺服器端之「Form異動紀錄表」及使用者端之「Table異動紀錄表」。本研究依資料表建構出用於行動裝置應用系統資料同步之資料預載及回存模組，希望能與未來行動裝置系統相關研究分享經驗，將此模組推廣及改善，提升系統的實用性及效能。[[abstract]]Currently, the mobile application development is increasing; one of the common uses is through a mobile database. But considering the environmental and network problems, they might influence data synchronization between mobile devices and server databases. There is still no module or product that can reach the data synchronization between server and mobile devices. Therefore, this study uses the web apps of long-term care systems as an example to resolve database synchronization problems between server and mobile device. The system can preload the data into the user's mobile device. Users can then add or modify the form data offline, and the system can automatically refresh the data online.The research framework of this study is divided into Data Preloaded Module and Data Uploaded Module. Data Preloaded Module is mainly dealing with downloading and updating data to the mobile devices that match the required tasks and user permissions. In order to improve the efficiency and use offline, Data Preloaded Module will check the data integrity when it is connected. Data Uploaded Module is mainly dealing with data recording; it would be modified in the mobile database and upload the data to the server database. During the work, two related tables have been analysed and used in the Data Preloaded Module and Data Uploaded Module. This study has constructed the Data Preloaded Module and the Data Uploaded Module for data synchronization. We hope to share experiences for mobile systems research in the future, promoting and improving this module, and increasing system performance and usability