Method for data synchronization and update conflict resolution between mobile clients and server in mobile system

• US 20040122870A1
• Filed: 04/25/2003
• Published: 06/24/2004
• Est. Priority Date: 12/24/2002
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Kim, Joong Bae, Park, Joong-Ki, Son, Duk Joo
• Granted Patent: US 7,543,047 B2
• Time in Patent Office: Days
• US Class Current: 707/201
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users

Abstract

Disclosed is a method for data synchronization and update conflict resolution between mobile clients and a server in a mobile system which maintains consistency of data between the clients and the server and enables the clients to continuously perform an effective update operation with respect to objects of the server even in a clients'"'"' disconnection state by the mobile clients performing an independent update operation with respect to disjoint fragments and associated objects for a specified object using the structure of the objects and the meaning of applications and then performing the data synchronization and the conflict resolution between the clients and the server during a reconnection operation. The method includes a copy management step of copying data of a server-side DB into a client-side built-in DB and the server managing contents of copying and a copying time, a data synchronization step of synchronizing changed data between the mobile clients and the DB server with respect to a data change produced during the mobile clients'"'"' disconnection state in accordance with a request of the mobile clients after a reconnection of the mobile clients, and a conflict detection and resolution step of detecting an error that damages consistency of the data in the data synchronization process and resolving the detected error.

Claims

1. A method for data synchronization and update conflict resolution between a plurality of mobile clients and a database (DB) server in a mobile system, the method comprising:

a copy management step of copying data of a server-side DB into a client-side built-in DB and the server managing contents of copying and a copying time;

a data synchronization step of synchronizing changed data between the mobile clients and the DB server with respect to a data change produced during the mobile clients'"'"' disconnection state in accordance with a request of the mobile clients after a reconnection of the mobile clients; and

a conflict detection and resolution step of detecting an error that damages consistency of the data in the data synchronization process and resolving the detected error.

2. The method of claim 1, wherein in the copy management step, the mobile client checks out from the server and copies into its own DB main object disjoint fragments for a specified object used during the disconnection state and its subsidiary object, and the server makes the checked-out subsidiary object copied in duplication by the plurality of mobile clients and makes the checked-out main object fragments not copied in duplication into other clients through a logical removing.

3. The method of claim 1, wherein in the copy management step, the mobile client requests the necessary object disjoint fragments by submitting to the server information on a checkout main object name, a fragmentation selection standard of the checkout main object, and a checkout subsidiary object list, and the server performs a fragmentation of the corresponding object to be checked out as the main object in the database according to the checkout main object fragmentation selection standard, and transmits the disjoint fragments and copies of the checkout subsidiary objects which are in a write-subordinate relation with the disjoint fragments to the mobile client.

4. The method of claim 1, wherein in the copy management step, as the mobile clients perform a write operation with respect to a checkout subsidiary object, the server prepares and manages a reconciliation (RC) list for the client that checked out the checkout subsidiary object, and the RC list comprises mode for the mobile clients that performed the write operation with respect to the checkout subsidiary object.

5. The method of claim 4, wherein the rnode comprises a log sequence number that is a log record number for the specified write operation of the checkout subsidiary object in a log file maintained by the server DB, and a time stamp that is information on a write-operation performing time.

6. The method of claim 1, wherein the data synchronization step is performed according to a specified reconciliation (RC) protocol, and comprises the steps of:

the mobile client reconnecting to the server and requesting an RC work for the disconnection period;

the server checking the RC list and transmitting a time stamp value of firstly produced mode among non-transmitted modes by checkout subsidiary objects to the mobile client that requested the RC;

the mobile client searching whether a referential transaction produced after the time stamp exists, and if the referential transaction exists, requesting the RC information to the server, while if not, informing that the RC is unnecessary;

if RC information is requested, the server transmitting information on the non-transmitted modes for the client, and if the RC information is unnecessary, transmitting a newest value of the checkout subsidiary object;

the mobile client performing the RC work by combining the mode information transmitted from the server; and

if the RC work of the mobile client is completed, the server removing the mode information transmitted to the mobile client from the RC list.

7. The method of claim 1, wherein in the conflict detection and resolution step, the mobile client detects the conflict in a referential transaction that uses the checkout subsidiary object by combining the mode information from the server with its own log, and if the conflict is detected between the referential transaction and the log information of the mode, undoing the referential transaction and resolving the conflict according to a specified rule of a compensation transaction.