DB WebApp; Requires Multiple Windows for Data Entry ?

Heavy Database Application (formerly on MS Access platform)
?? Requires Multiple Windows for Data Entry ??

There are a number of different tables and entities that would be
helpful to access and modify through separate browsers.
I'm assuming the user is intelligent enough to understand refresh and
concurrency issues.
Other issues: $$ format fields, sorting tables, type-a-head prompting,
etc.. Assuming open source (php/mysql), but am also considering a
Java Applet front-end.
Any advice, Comments ?

invinfo (AT) rcn (DOT) com writes:

There are a number of different tables and entities that would be
helpful to access and modify through separate browsers.
I'm assuming the user is intelligent enough to understand refresh and
concurrency issues.

Intelligence isn't enough. It's non-intuitive that if user 1 is
modifying field A and user 2 is modifying field B, that one of the
changes won't take.

To alleviate the concurrency issue with a web interface, have hidden
variables with the old values, and only update fields where the new
value is different from the old value. That system will behave the way
most intelligent but uninformed users would expect. For an extra guard
against users not paying attention to concurrency issues, signal an
error if the old and new values differ, but the current database value
doesn't match either.