Can anyone suggest me a how to go abt this requirement thats came up and needs to be answered immediatly.Wud be grateful if anyone can suggest me a way.



We have a 3 tier client server app.



Client PC

Server PC

Database Oracle (usually on SUN servers) - The database can be VERY large.



Currently the client PC's must be permanently attached to the server in order to operate.





ENHANCEMENT



We want to be able to allow mobile PC's to operate when they are not connected to the main system (ie standalone).

Our current plan is to install all of the tiers on the mobile PC (laptop) so that the application would run standalone on the mobile PC and have its OWN copy of a database.



But...

The entire database would not fit on the PC so it would need to only hold a (configurable and dynamic) subset of the data in the main database (organised around the workload of a particular user).

Changes that the user made on the local database must be synchronised to the main database when the user connects to the permanent infrastructure - we would like the connection mechanism to be as flexible as possible. (Similarly changes made in the main database must be synchronised to the local database)

It is NOT sufficient to synchronise only the 'end' state as the main database needs to record all of the transactions that the user made with the database along with the time and date the changes were made (ie not time stamped at sync time).



And...



Ideally we do not want to have to change the client or server software in order to provide the mobile functionality.

We want to be able to change the client and server software without having to modify the synchronisation mechanism (other than simple configuration changes)

We want the database structure to be the same on both mobile and main systems

We want to be able to add additional tables, stored procedures, triggers etc. to the database without having to change the synchronisation mechanism (other than simple configuration changes)

And pretty obviously we will need to be able to define what happens when both the mobile and server database have changed



Thnx & Regs

Rana


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