Maintaining a transaction across multiple HTTP requests

Hi all,

I need to write a server script that will be used to synchronise a SQL Server CE database on a Pocket PC with a central PostgreSQL database. Ideally, what I'd like to do is pass modifications made on the PPC to the script which then begins a transaction (thus ensuring no futher data changes will be seen by the client) and checks for any conflicts with changes made on PostgreSQL since the last synchronisation. If there are any, the script will return details to the client for conflict resolution. When the planned conflict resolution is returned by the client, the required updates are executed within the original transaction which is then committed.

The difficulty with this plan is that the transaction must be maintained across 2 or more individual http requests (which may normally be serviced by different Apache child processes of course, thus preventing storage of a connection handle in a session variable). Is there conceivable way I can achieve this, or should I go back to the drawing board?

Regards, Dave.