External database changes -> Hibernate -> Client

An existing external system makes regular (every few seconds) updates to several database tables. We want to build a dashboard type user interface which allows the user to view additional records and important updates in near real-time. The user interface would also allow some transactions which would result in database changes.

Our thoughts are to use a stack with Hibernate and Flex (see http://dl.dropbox.com/u/1431390/overview.jpg) but we are open to using any free/open source technology. There are a few issues we are unsure about should we use our proposed stack:

1) How to automatically update the POJOs with database changes? As far as I understand it, there is no way of hibernate knowing about any changes made outside its own session. Therefore, some sort of polling would have to be done to pick up new and changed records.

2) We were planning to push the data to datagrids within a flex UI (using BlazeDS or WebORB). This seems to rely on identifying the changes and pushing these as updates down the channel. However, if we use the Hibernate->POJO approach identifying these changes could be fairly complex a开发者_开发百科s we have refreshed the data. Is there a better solution which will push the changes on the fly? I would have thought this was a common requirement but I can't find much information online.

Any advice would be gratefully appreciated on either the architecture or the specific issues.

Many thanks,

Ken

For 1) - Use polling or if you have enough budget use a database that supports pushing JMS messages from triggers (DB2, Oracle, MSSql server).

For 2) - There is a commercial product built by Adobe which can solve this problem easier (it has this feature that you are looking for). It has a steep learning curve and is targeted for enterprise. Otherwise you will have to implement your own solution - refresh only the changed data etc.