One (small) advantage that JDO tools (e.g. Kodo) have over tools that use reflection (e.g. Hibernate) is that they persist the internal state of your class and do not care about the interface.
When using reflection, it is assumed that the class always has a default public constructor, and every persistable field has the corresponding JavaBean style getter/setter methods. This can lead to classes that aren't properly encapsulated (for example, an object may have certain immutable fields that can only be set upon creation). Other than that, the net effect is very similar. -JoeW > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Christoph > Sturm > Sent: 10 April 2002 13:47 > To: Marco Pas > Cc: [EMAIL PROTECTED] > Subject: Re: [Mav-user] What are you all using to build database driven > we bapps? > > > Hi Marco! > > Torque is a low level persistence framework, you must take care of > relationships between tables yourself. > Hibernate supports relationships, self references, and some really nice > stuff like lazy maps containing other maps, and now even caching. It can > also generate mapping descriptors from java classes, and ddl from > mapping descriptors. > Castor is a odmg implementation, but it has some problems, for example > limited support for inheritance, and no support for self references. > For this style of persistence engine I'd recommend > ObjectRelationalBridge (http://sourceforge.net/projects/objectbridge/), > which is also an odmg implementation. > jdo implementations like kodo use a bytecode enhancer, which means one > more step in project building. All other frameworks work just with > simple java beans. > > I would recommend object relational bridge or hibernate, depending on > your needs. Hibernate is much more lightweight, and its also easier to > get started with it. ojb is much more complex, but it can pay off if you > need the caching. I really cant recommend castor because it has some > conceptual problems, and a very complex codebase. I had some real > problems with it, and use ojb now for stuff that used castor before. > > hth > chris > Marco Pas wrote: > > >Can anyone suggest some differences then between Torque, Kodo > and Castor ? > > > >Why pay money for a product if you can use it for free, this in > relation to > >Kodo and Torque.. > > > >Marco > > > >-----Original Message----- > >From: Joe Walnes [mailto:[EMAIL PROTECTED]] > >Sent: woensdag 10 april 2002 10:48 > >To: [EMAIL PROTECTED] > >Subject: RE: [Mav-user] What are you all using to build database driven > >webapps? > > > > > >Similar story here - I've been using Orion's EJB persistence (which is > >awesome!) for a while, but I'm really trying to move to a > simpler solution > >now. A very crucial criteria for me is ease of use - I don't want to be > >continuously writing database support classes, modifying schemas and > >updating XML mapping files (within reason of course). EOB seems like the > >choice for hosting my components. For persistence, (after trying about 10 > >gazillion tools) Kodo is my preferred tool. > > > >Kodo is an incredibly elegant commercial JDO implementation - pricing is > >reasonable. It supports very sophisticated object/relational mappings > >including inheritance and reverse lookups. The nicest thing > about it is how > >little work you (the developer) have to do; the source for > existing classes > >doesn't need to be modified or conform to a particular pattern to be > >persistant. The tools modify the bytecode of existing classes, > generate the > >schema for you (complete with database optimizations) and even alter an > >existing one. > > > >If a commerical product is out of the question, these systems I also rate > >highly: > >- Castor: Very mature JDO like system. > >- Hibernate: Quite young system similar to Castor although much > simpler to > >work with. > >- OfBiz Entity: Very robust persitence system, based on generic value > >objects rather than classes (although values can be wrapped with > classes). > > > >Depending on the domain logic approach I'm using, I'd choose OfBiz for a > >transactional script approach and Hibernate for a domain model. > Of course, > >my first choice would be Kodo for both of these - when I can use it! :) > > > >Hope this helps. > > > >Kodo: http://www.solarmetric.com/ > >Castor: http://castor.exolab.org/ > >Hibernate: http://hibernate.sourceforge.net/ > >OfBiz: http://www.ofbiz.org/core/docs/entity.html > >Orion: http://www.orionserver.com/ > >Domain logic blurb: http://www.martinfowler.com/isa/domainLogic.html > > > >Regards, > >-Joe Walnes > > > >>-----Original Message----- > >>From: [EMAIL PROTECTED] > >>[mailto:[EMAIL PROTECTED]]On Behalf Of Jeff Schnitzer > >>Sent: 10 April 2002 07:30 > >>To: Marco Pas; [EMAIL PROTECTED] > >>Subject: RE: [Mav-user] What are you all using to build database driven > >>webapps? > >> > >> > >>Funny that you ask that. I've started rewriting the Similarity > >>application, in the process moving it to JBoss. Basically, I'm sick of > >>obfuscated stack traces with no useful error message from Orion. > >> > >>I got a little frustrated for a bit, so for a little while I vaguely > >>considered ditching all the EJBs and going with a much simpler solution. > >>I spent a large part of yesterday researching Torque. As a persistence > >>framework, I'm quite impressed with it. For the next application I > >>start, I'll probably use it, maybe with EOB (http://eob.sf.net) to > >>provide three-tier support. > >> > >>Torque is fairly mature; it has been used to implement Scarab > >>(http://scarab.tigris.org), so I feel fairly confident that it will > >>accommodate a pretty wide problem domain. It should also perform a lot > >>better than an EJB solution because it's a *lot* lighter weight. > >> > >>All that said, I think I'm going to stick with EJBs (and entity beans) > >>for Similarity, if only because I can reuse a lot of the existing > >>system. But if you aren't already wedded to EJBs, I would take a good > >>look at Torque. > >> > >>Jeff Schnitzer > >>[EMAIL PROTECTED] > >> > >>>-----Original Message----- > >>>From: Marco Pas [mailto:[EMAIL PROTECTED]] > >>>Sent: Tuesday, April 09, 2002 10:50 PM > >>>To: '[EMAIL PROTECTED]' > >>>Subject: [Mav-user] What are you all using to build database driven > >>>webapps? > >>> > >>>Hi, > >>> > >>>I am really curious what you guys/girls are using to build database > >>> > >>driven > >> > >>>webapps (not ejb). > >>>Maverick and Struts both solve the MVC problem but they do nothing to > >>> > >>make > >> > >>>my life easier when working with databases. > >>>I can set-up a nice MVC structure but then it comes down on hand > >>> > >>coding > >> > >>>the > >>>java - classes that do > >>>database access and implement the CRUD principles. I am really getting > >>>tired > >>>if this ;-) > >>> > >>>I read about Castor / Apache Torque / JDO etc.. but what > >>> > >>framework/tools > >> > >>>are > >>>you all using to simplify this kind of > >>>functionality ?? Any hints and tips are highly appreciated. > >>> > >>>-= The trouble with work is ... it's so daily ! =- > >>> > >>>Greetings, > >>>Marco Pas > >>> > >>>_______________________________________________ > >>>Mav-user mailing list > >>>[EMAIL PROTECTED] > >>>https://lists.sourceforge.net/lists/listinfo/mav-user > >>> > >>_______________________________________________ > >>Mav-user mailing list > >>[EMAIL PROTECTED] > >>https://lists.sourceforge.net/lists/listinfo/mav-user > >> > >> > > > > > >_______________________________________________ > >Mav-user mailing list > >[EMAIL PROTECTED] > >https://lists.sourceforge.net/lists/listinfo/mav-user > > > >_______________________________________________ > >Mav-user mailing list > >[EMAIL PROTECTED] > >https://lists.sourceforge.net/lists/listinfo/mav-user > > > > > > > > > > _______________________________________________ > Mav-user mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/mav-user > > _______________________________________________ Mav-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mav-user
