Re: Mixing OO and DB
Date: Fri, 29 Feb 2008 12:59:45 -0500
frebe <frebe73_at_gmail.com> writes:
>> Not true. The state of each element in the set of root
>> objects may be constructed from complex queries over multiple
>> tables. The objects reached from those root objects may be lazily
>> loaded, again with complex queries. Regardless of the complexity
>> of those queries, there is typically no proliferation of finder
> I have seen a lot of finder proliferation in many different
> applications. You might claim that those applications are not well-
> written, but they do exits.
I don't dispute that. I'm saying that, in my experience with large distributed systems, the proliferation of finder methods is an indication of poor design and/or misuse of the available technologies.
>> >> Typically, once a core set of objects have been instantiated,
>> >> access to related objects is via reference rather than repeated,
>> >> explicit database access.
>> > And obviously introducing synchronization issues...
>> You are assuming that the database is always the system of
>> record and that the system is data-centric. Those assumptions are
>> not always valid so your "obvious" synchronization issues do not
>> occur. There are more ways of building large scale distributed
>> systems than are dreamt of in your RDBMS.
> Having mutable data structures in multi-user applications, will
> cause synchronization issues.
That's a different statement than claiming that those synchronization issues are somehow due to mapping from a relational model to an object model. There are many ways to address the synchronization issues inherent in distributed or multiuser systems. An RDBMS is only one of those.
S P Engineering, Inc. | Large scale, mission-critical, distributed OO
| systems design and implementation. pjm_at_spe.com | (C++, Java, Common Lisp, Jini, middleware, SOA)Received on Fri Feb 29 2008 - 18:59:45 CET