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>>Our case is simpler than yours in that we can use the record comparison method, as it only takes 2 or 3 minutes at the end of the day. Record by record comparison is much easier to implement and less prone to errors, although is not always suitable because it's more time demanding.
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>We started out using a record by record comparison, but found that we were stepping on each others modifications. TabletPC A would modify Field 1, 2 and 3 in record 1 while TabletPC B would be modifying Field 4, 5 and 6 in record 1. So it became a big nightmare to sync up and not loose any modifications. What our solution has been to fire triggers on Updates where we capture not only the record modified, but also which fields in the record have been modified. We record the original value along with the new value for each modified field. This has allowed us to sync up to the central database and not be concerned when TabletPc A or TabletPc B syncs up (today or not). Our audit trail gives us a timestamp on each modified field in each modified record and works quite smootly (so far) Time wise, we can sync up around 26,000 records (one or more fields per record) from around 45 to 75 seconds per sync. We do have collisions once in a while and so far been able to work around it.
>Problem is if TabletPc A and TabletPc B create a child record with identical information, we have 2 different pk's and hence 2 records are added. So we have to monitor that by case by case.
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>The whole idea of syncronization has really been a challenge but not impossible. It is enjoyable hearing from others that are doing similar issues as we are. Good luck to you as well.

I have not tryed hard to include the whole routines in the trigger that fires on update to track records and fields modified, but I will play around it.
Actually we don't do record by record, but make comparisons based on the primary keys of tables to avoid differences due to packs.
As I told you my biggest concern up to date is customers ordering in two different places in the same day, or next day if the shop could not make an update from the central server.