Data base synchronizing system with at least two host databases and a remote database

• US 6,466,951 B1
• Filed: 02/08/2000
• Issued: 10/15/2002
• Est. Priority Date: 02/10/1999
• Status: Expired due to Term

• Current Assignee: Optis Wireless Technology, LLC (Brevet Capital)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Olsson, Patrik, Novak, Lars, Birkler, Jörgen
• Primary Examiner(s): Breene, John
• Assistant Examiner(s): Wong, Leslie
• Application Number:
  US09/499,348
• Time in Patent Office: 980 Days
• Field of Search: 707/8, 707/10, 707/201, 707/202, 707/204, 709/248
• US Class Current: 1/1
• 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

A database system has at least two hose databases (204, 214) in respective host processing apparatuses (200, 210). A remote database (224) is provided in a remote processing apparatus (220). The host databases and the remote database store a plurality of database items. A synchronization engine (206, 216) is provided in each host processing apparatus for synchronizing its host database with the remote database. A first log file (227) contains entries, that represent changes made to the remote database (224), including additions and modifications of items in the remote database as well as deletions of items from the remote database in order to increase its free storage space available for storing new items. A second log file (229) contains entries, that represent deletions from the remote database upon respective deletions in either of the host databases (204, 214). The synchronization engine (206, 216) deletes items in its host database in accordance with the entries in the second log file but not in the first log file.

Claims

1. A database system comprising:

at least two host databases in respective host processing apparatuses;

a remote database in a remote processing apparatus, where the host databases and the remote database are adapted to store a plurality of database items;

a synchronization engine in each host processing apparatus for synchronizing its host database with the remote database;

a first log file having entries representing changes made to the remote database, including additions and modifications of items in the remote database as well as deletions of items from the remote database in order to increase its free storage space available for storing new items; and

a second log file having entries representing deletions from the remote database upon respective deletions in either of the host databases,

wherein the synchronization engine is adapted to perform deletions of items in its host database in accordance with the entries in the second log file but not in the first log file.

2. A database system according to claim 1, wherein the remote processing apparatus is a portable digital assistant.

3. A database according to claim 1, wherein the remote processing apparatus is a mobile telephone.

4. A database system according to claim 1, wherein at least one of said host processing apparatuses is a desktop computer or laptop computer.

5. A method of synchronizing at least two host databases and a remote database, comprising:

providing a first delete command for deleting items stored in the remote database, when the remote database is full,

providing a second delete command for deleting such items from the remote database which have been deleted from either of the host databases,

maintaining a first log file for keeping track of items which are related to the first delete command, and

maintaining a second log file for keeping track of items which are related to the second delete command.