Sometimes the simplest answer is the best... and even when it isn't the best, it's *still* simple :) ...
How about just creating a new DAO/DTO that only contains the data you need? It would be a duplication to a degree, but that's not *always* an absolutely evil thing... especially since it sounds like the new A object you want to display on the page may not truly model a real domain object (where they others I presume are) but is instead something of a hybrid, I could personally live with this. Either that, or I would just create a single Miscellaneous DAO that has methods that don't *quite* fit in other DAOs... maybe this is one of them... then you would still have a DTO for this particular case, and a new one for each particular case in the DAO, if any more came up. FYI, most of my apps have the true DAO/DTOs, but they all also have such a miscellaneous class for handling things exactly like this. There tend to be very few such cases, but they do come up, and I find this to be a nice way to organize them. In fact, in a couple of cases I've decided to make the DTOs inner classes of the DAO, just to make it obvious they are related and probably limited in their use cases. -- Frank W. Zammetti Founder and Chief Software Architect Omnytex Technologies http://www.omnytex.com On Thu, August 18, 2005 8:00 am, Tom Ziemer said: > Hi everybody! > > In my app, I am using DAOs/DTOs to perform CRUD operations on a legacy > database packed with lots of triggers and stored procedures. Some of my > DTOs are pretty complex, meaning, they have to be assembled from many > tables. > > A simple example: > Object a (loaded by aDAO) has a list of b objects (loaded by bDAO), > which in turn has a list of c objects (loaded by cDAO) > > The problem: > In my struts-based webapp, I want to display some a objects on a page > (the objects won't be used after that anymore). I need a few attributes > from related object b but nothing at all from the related c objects. > When I use my aDAO to retrieve my a objects, this will cause a large > number of sql queries (1 per object), resulting in lots of data I do not > need. > > The question: > Wouldn't it be more effecient to use a single query, that only loads the > required data? This would mean though, that I cannot use my DTOs. > > Any thoughts? > > Regards, > Tom > > --------------------------------------------------------------------- > 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]
