Hello Rice,
> Hi, > I have been using OJB for some period. I am taking a > project left by a partner that uses Hinbernate for > persistence. So I start studying Hibernate. Hibernate > has a mapping function called "any type mapping" that > is defined as the follows: > > "The <any> mapping element defines a polymorphic > association to classes from multiple tables. This type > of mapping always requires more than one column. The > first column holds the type of the associated entity. > The remaining columns hold the identifier. It is > impossible to specify a foreign key constraint for > this kind of association, so this is most certainly > not meant as the usual way of mapping (polymorphic) > associations." > > This kind of mapping is quite useful when dealing with > fields of java.lang.Object or interface. However, as I > know, there is no such support in OJB. That's not true! OJB allows to build completely polymorphic mappings. Just have a look at the o.a.ojb.odmg.collections.DListImpl class. It is a list implementation that can hold elements of arbitrary persistent classes. The trick is that we store serialized Identity objects as "pointers" to the actual objects. If you look at the DListImpl code you will see how easy it is. cheers, Thomas > I try to study > the source code of OJB, but am still not able to > figure out the way to modify it (The xml mapping > handling code is a little hard to understand, just > wonder if it is possible to re-write it with Jibx to > make it more concise). > > Regards, > Rice > > > __________________________________ > Do you Yahoo!? > Exclusive Video Premiere - Britney Spears > http://launch.yahoo.com/promos/britneyspears/ > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
