On 3/9/07, Uday Kamath <[EMAIL PROTECTED]> wrote:
We had similar use case. What we do is we model the Schema elements, generate Java Beans (pojo), and write rules using these Pojo. Now we have written a Service on top which takes Hibernate QL and gets the database records as the same Pojos that Rules are defined on and fire the Rules. Thus the service is generic and can be changed to take any Query. The Rules can me modified and changed anytime and redeployed but business objects in form of Pojos remain the same. Hope this helps -Uday ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Joe Chuby Sent: Friday, March 09, 2007 3:53 AM To: rules-users@lists.jboss.org Subject: [rules-users] Using rules with database scenario Hi all, First time trying to learn JBoss Rules here. We have a pretty large database (DBMS), we want to build some rules and retrieve data based on the rules. Could someone give a hint or an example of this usage scenario? I mean, how can I use rules for database query, without writing my rules in SQL directly? We are currently writing everything in HQL (Hibernate), but the rules change every 3 months on average, so that's not a way to maintain the system. Therefore, we want to extract that portion of the business logic out of the code. The data structure does not change, but the rules keep on changing. I'm reading the user's guide, running thru the examples, writing some of my own, but still no clue how to make it work with database. If someone could give a sample, that would be greatly appreciated. Thanks a lot.
That's probably the best solution. Using the current version (3.1M1), you can use the FROM keyword to reference facts from List object returned from a method call on a service, for example. Something like this works very good in my current testing project: rule foobar when MyObject( someValue = "foobar" ) from MyObjectDAO.loadAll() then ... end The DAO then uses Hibernate to load some objects and returns a List<MyObject> which can be used by Drools. As Uday already wrote, you could also write a DAO which retrieves arbitrary objects using a given HQL statement. Best regards Marcus _______________________________________________ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
