How to see changes in database made by other users

Question

If few users are connected to one database what should be done that all users could see changes (updates, inserts) made by one of them?
I have set conn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED);
and statement = DatabaseConnection.conn.createStatement
(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
but phrase dmd.othersUpdatesAreVisible(ResultSet.TYPE_SCROLL_SENSITIVE) returns false.
I will be grateful for any help

Answer 1

I was thinking about it, but the possibility of of
refreshing data without users beinig involved and
only when it is needed Something of a contradiction. If the user is not involved then you don't know if the information is needed or surplus to requirements.
seems more elegant to meOn the contrary - it's an architectural kludge. Solutions of this type are fragile. This may be acceptable in return for an improved user experience, but you need to weigh this particular improvement against possible degradation elsewhere as a result of it.
Databases are designed to be queried. You're trying to have the database notify you. Given this you will have to trade some quality in return for the feature you're after.
Note also that transactionality is pretty much about avoiding the scenario (views on incomplete or conflicting transactions) that you're seeking. Given how much effort goes into avoiding this are you absolutely sure you've thought through the possible consequences of it? What about transactions that get rolled back and thus (effectively) never occur, for example - should your users be able to see these?
So, your trade-offs are:
Polling - Pro: gives you the behaviour you ask for. Con: Fragile, may cause performance problems, possibly unwise for business reasons. Have you performed usability testing (http://useit.com/) to ensure your users actually need this?
Manual updates - Pro: reliable, performant, ACID. Con: Not the dynamic behaviour you ask for.
There are two other possibilities which have not been discussed. I mention them for the sake of completeness, but I don't recommend them.
Database Notification - Pro: as manual. Con: not a portable solution; if possible at all you will need to take advantage of database specific features such as triggers and Java stored procedures. Adds considerable complexity to the database layer and thus requires alert and informed DBAs (worth their weight in gold).
Application Notification - Pro: portable to some extent. Con: agnostic about updates occurring outside your application. Requires a solid architectural base to be robust.
(edit: after re-reading the OP, I'm not sure if he does or does not want to see incomplete transactions; disregard those points if he doesn't.)