Re: Mixing OO and DB
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Fri, 29 Feb 2008 13:12:16 -0400
Message-ID: <47c83cf1$0$4069$9a566e8b_at_news.aliant.net>
>>frebe <frebe73_at_gmail.com> writes:
>>
>>>> I tried to be very clear with what I was saying. In the large
>>>>OO systems that I've worked on, there was no problem with
>>>>proliferation of finder methods in practice.
>>>
>>>In applications there problem with proliferation of finder methods
>>>doesn't exists, the find methods have to be very simple, like
>>>"select * from employee where id=?". Otherwise the problem do
>>>exists.
>>
>> 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 methods.
>>
>>
>>>>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.
Date: Fri, 29 Feb 2008 13:12:16 -0400
Message-ID: <47c83cf1$0$4069$9a566e8b_at_news.aliant.net>
David Cressey wrote:
> "Patrick May" <pjm_at_spe.com> wrote in message news:m2ir073ms9.fsf_at_spe.com... >
>>frebe <frebe73_at_gmail.com> writes:
>>
>>>> I tried to be very clear with what I was saying. In the large
>>>>OO systems that I've worked on, there was no problem with
>>>>proliferation of finder methods in practice.
>>>
>>>In applications there problem with proliferation of finder methods
>>>doesn't exists, the find methods have to be very simple, like
>>>"select * from employee where id=?". Otherwise the problem do
>>>exists.
>>
>> 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 methods.
>>
>>
>>>>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.
Patrick evidently underestimates my imagination.
[snip] Received on Fri Feb 29 2008 - 18:12:16 CET