Hello

I'm developing an application that will be used in five different
locations and each night the databases should be synchronised to
contain identical data ready for work the following day.

At present, I'm tending towards having all the satellite offices
sending the data to the head office, where the data gets synchronised
and then sent back to each office. How do people do this - dial up
using a modem / as an email attachment(!) / posting to a website?
Can a process connect to another Firebird server via dialup and fire
SQL over the line to get any changes?

I think I need to give each row a branch ID and possibly
a 'LastChanged' timestamp, so that only changed records can be sent
to the headoffice, but what about deleted rows and rows where
multiple offices have made changes to the same row? Or, is it best
to have duplicate tables which initially start the day empty, and
gradually fill up during the day (via triggers) with changed entries?

I'm looking for any tips/pointers on how to achieve this.

TIA

David