Hi Martin, I assume you want to use EJB 1.1 CMP since there are a plethora of j2ee 1.2 certified application servers around. But the EJB 1.1 was relatively weak in the sense it did not specify how (or even if) an EJB server vendor provided features to define & manage relationships between (entity) beans. The EJB 2.0 specification does set this straight - but it is going to be some time before vendors are certified ejb 2.0 compliant. (There are vendors that are supporting parts of the ejb 2.0 specification already)
However with current 1.1 (certified) implementations on the market, I would suggest you take a look at different vendor offerings to see if (and then how) they implement this with CMP. Some might even 'delegate' this to a third party tool like TopLink. I would suggest (it is a suggestion only) that you take a look at the Borland AppServer as it has some strong O/R mapping features built into the CMP engine itself. See section "EJB Entity Beans" in the document "Features and Benefits" (PDF) at http://www.borland.com/appserver/ The product itself is available as a trial download and there are some examples & documentation that illustrate how relationships work with our product. -krish To: [EMAIL PROTECTED] Subject: Coarse vs Fine Design Question I'm a relative newbie to J2EE and I'm in the process of developing an application using this technology. My intent, from the beginning, is to apply best practices and Sun's pattern catalog and the excellent Core J2EE Patterns seems to have this pretty much covered. The problem I'm having is finding simple examples that demonstrate how to apply this stuff. Or put it another way: my brain seems stuffed with theory by I don't know where to start in practice. What, for example, is the best way to model an invoice where there is a many-to-one relationship of invoice lines to header? Should I model this as a CMP bean for header, a CMP bean for lines and an Invoice stateless session bean that manages the CMP beans? Should I model this as a single Invoice BMP bean? This is my interpretation of the Aggregate Entity model pattern. Is my interpretation correct? Should I carry on reading books for a while longer because these questions get answered by every book on ejb's anyway? :) Is this the right list to pose questions like this? Thanks for any help. Martin =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff EJB-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
