Hemant Khandelwal wrote: > > Note that cmp-fields in EJB 1.1 CMP entity beans are stored as state > variables. Hence callback, when cmp-fields are modified, is not made on the > Container. Therefore, EJB 1.1 Container vendor cannot provide optimized > access to persistent store in a standard way. Though, some EJB 1.1 Conatiner > vendor provide such optimization in a vendor-specific way. Although it is true that callbacks do not occur in EJB 1.1 to indicate that a CMP field is modified, it is not particularly hard for an EJB 1.1 Persistence Manager to detect which fields were modified at store time. This information can be used to suppress the update if the bean was unmodified. This provides high-performance support for read-only access, without requiring a proprietary "isModified()" method. <vendor> We use this technique in Borland AppServer to provide not only suppression of updates for read-only access, but also to provide "tuned updates" (whereby only the fields that were modified are updated) and "verified updates" (whereby we verify that the record was not modified during the transaction, which could occur in the case where the record was not locked in the database at load time). See my posting: Real-world limitations of simplistic optimistic concurrency schemes for further details. It can be found at: http://archives.java.sun.com/cgi-bin/wa?A2=ind0009&L=ejb-interest&P=R75066 </vendor> -jkw =========================================================================== 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".
