Take your postgresSql on the road, and live to tell of it.

Here's what I want to do:

Checkpoint the database in whatever way is appropriate.

Make copies of the database on several laptops for use in the field 
(in automobiles) to do database changes.  Record all the changes made 
since the checkpoint as the user makes them.

Periodically take all the changes back into the office, take the 
changes made out in the field and apply them to the main database.

Repeat the process.

Notes:

1) Unless an user makes a mistake, there should be no changes to the 
same records by multiple users.  (i.e. any concurrency violations 
should be registered as an exception.)

2) I'd prefer it to just record the sql commands executed by the 
database as text, then use psql < myFieldcommands to update the 
database.  This will also help me isolate any concurrency exceptions, 
and I'd like to wrap the whole update in a transaction, so I can roll 
the whole thing back if it does detect concurrency problems anywhere 
in the process (then I can edit out the offending lines).

3) There's no particular rush to update the database - I don't need 
this real-time.

4) Users might make their checkpoint at a different time from other users.

Since I'm relatively new to Postgres, (and I apologize if this has 
come up before), I'm hoping some respondents will provide me with the 
correct strategy.

-Owen