Database Synchronization Model Research Based On Repack Correction

With the development of information technology and the popularity of the network environment, the enterprises are increasingly focusing on information sharing and data exchange in the information construction process. However, because of the departments different locations, and the heterogeneity between various kinds of databases, how to make data synchronization effective, safe and accurate between heterogeneous database is a important issue that urgently need resolving in application system of modern enterprise.At present, commercial database synchronization programs widely used, are divided into two types. Large database vendors put forwards their heterogeneous database synchronization program in the isomorphic synchronization of their own database product. Independent software developers (ISV) have developed a great number of database synchronization middleware which have the function of heterogeneous database synchronization, and been generally accepted in the market.However, there are some disadvantages in the commercial products of heterogeneous database synchronization:closure; unopened code; unified standards; it's difficult to achieve interoperability in different database synchronization products. And current programs in the academia have deficiencies in efficiency, versatility, openness, and synchronization.To solve the above problems, the paper designs and implements a database synchronization model based on repacks correction. Main tasks are summarized as follows:1. Combine the change track table with transaction to capture the changed data in the database. To ensure that the data operation information and the change track information are consistency. The change track table is efficient, taking up a little storage space, and easy management.2. By way of the advantages of XML, such as the platform-independent, easy extensibility, interactivity, semantic, etc, it can pack and unpack the change track table into document,,for achieving the heterogeneous databases synchronization.3. By way of the message queue middleware for data transmission, it can ensure the sequence of XML data transmission, and improve the data security.4. Combine the priority with time stamp technology to solve data conflicts. Manually setting the priority is for convenience and flexibility while comparing the time stamp of data modification time is for reality to improve the accuracy of the data. 5. Using the repack correction method, to solve the synchronization failed. Through verification detection monitoring database synchronization, after repack correction the failed XML document, then resend. Mainly to solve the synchronization process in the database, the failure because of accident data packet loss, or unpack synchronization failure error, etc., to result in the data inconsistency between sender and receiver. By the repack correction method avoid the "dirty data" appears, and get the clean, consistent data.Finally, experiments prove that the Database Synchronization Model Based on Repack Correction is practicable. This mechanism also was applied in a pharmaceutical remote monitoring platform at Food and Drug Administration District in ChongQing. And it has proved the feasibility of the theory, and the accuracy of data transfers.