Re: [Jaxor-devel] Re: Associating Lists

[Michael R. <mik...@ya...>]

Exciting news indeed. Drop me an email once you commit
and I'll have a look (and write some tests). If
everything passes, then we can look at pushing a new
beta release.

Mike


--- Carl Fyffe <car...@gm...> wrote:

> Exciting news. I have the core functionality
> working. I have bumped
> into a small conflict where one to many and many to
> many don't play
> nicely together. After I figure out the semantics
> and fix the
> isForeignKey() method that I introduced for the one
> to many, we will
> be in business. I expect to commit this week. It was
> a good weekend!
> Hope yours was as good as mine.
> 
> Carl
> 
> On Tue, 17 Aug 2004 21:33:33 -0700 (PDT), Michael
> Rettig
> <mik...@ya...> wrote:
> > Yes, it can be complicated. I guess I haven't
> > implemented anything b/c I haven't run across
> > situations where it was difficult to manage
> manually.
> > The code to manually update fields is trivial.
> Though
> > transparency has benefits too. Don't worry about
> > changing the DTD. Just change it so the new
> element or
> > attribute is not required and defaults to the
> current
> > implementation. I think adding an element or
> attribute
> > is the only way that this will ever work
> correctly. It
> > cannot always be automatic. There are always
> > exceptions. Certainly, we need an attribute to
> turn
> > off automatic relationship management.
> > 
> > Your example seems sensible, but would make more
> sense
> > to me with some unit tests. Do you have a use case
> > from an app you are currently writing? I usually
> > create a unit test that satisfies the requirements
> of
> > an app I'm working on in the simplest manner
> possible.
> > Then change the code to meet those requirements.
> > 
> > Regards,
> > 
> > Mike
> > 
> > 
> > 
> > --- Carl Fyffe <car...@gm...> wrote:
> > 
> > > I think I see why you have avoided this for so
> > > long... it is hard to
> > > know exactly what the user is going to want
> without
> > > resorting to the
> > > verbose hibernate style dtd. I am trying to
> avoid
> > > changing the DTD at
> > > all costs and trying to use the api as it exists
> to
> > > achieve the
> > > results we are looking for. The main problem I
> > > continue to run into is
> > > that of id generation and other things of that
> > > nature (filling in
> > > details of a linking table that don't
> neccessarily
> > > have anything to do
> > > with the links).
> > >
> > > Forgetting about the linking table details I
> would
> > > like to throw a
> > > theory out there.  Please tell me if this holds
> > > water.
> > >
> > >
> > >
> > > If there are entity ref's to multiple tables,
> the
> > > host table can be
> > > thought of as a many to many linking table of
> some
> > > kind.
> > >
> > > IE groupmembers has two entity ref's, one to
> groups,
> > > one to users.
> > > This means jaxor should generate a
> > > newInstances(group, userList) and a
> > > newInstances(user, groupList) method in the
> Finder.
> > > This is the easy
> > > case.
> > >
> > > Now, lets look at adding a third entity ref.  I
> > > couldn't figure out a
> > > sensible way to model this with users and groups
> so
> > > I am gonna go with
> > > the structure of XML.  Say we wanted to create a
> > > generic way to store
> > > XML in an RDBMS. We would have tables for
> documents,
> > > elements and
> > > attributes. If this was normalized we would only
> > > want one instance for
> > > each element and attribute. So if we go all the
> way
> > > down to the
> > > instance of an attribute we would have something
> > > like this:
> > >
> > > <jaxor
> > >
> package="net.sourceforge.jaxor.example.xml.jaxor">
> > >     <entity name="attribute_instance"
> > > alias="AttributeInstance" >
> > >         <primary-key>
> > >             <column name="attribute_instance_id"
> > > type="Long"/>
> > >         </primary-key>
> > >         <column name="element_instance_id"
> > > type="Long"/>
> > >         <column name="attribute_id"
> type="Long"/>
> > >         <column name="document_id" type="Long"/>
> > >
> > >         <entity-ref table="element_instance">
> > >             <key source="element_instance_id"
> > > target="element_instance_id"/>
> > >         </entity-ref>
> > >         <entity-ref table="attribute">
> > >             <key source="attribute_id"
> > > target="attribute_id"/>
> > >         </entity-ref>
> > >         <entity-ref table="document">
> > >             <key source="document_id"
> > > target="document_id"/>
> > >         </entity-ref>
> > >
> > >     </entity>
> > > </jaxor>
> > >
> > > The attribute instance points to a singular
> element
> > > instance, which in
> > > turns points to a concrete element. The
> attribute
> > > instance also points
> > > to a concrete attribute and document.
> > >
> > > In this case, we would want jaxor to generate a
> > > bunch of
> > > newInstances() methods....  We are only going to
> > > want three:
> > >
> > > newInstances(document, attribute,
> > > elementInstanceList)
> > > newInstances(document, attributeList,
> > > elementInstance)
> > > newInstances(documentList, attribute,
> > > elementInstance)
> > >
> > > I don't think it really makes sense to pass in
> more
> > > than one List.
> > >
> > > Of course it is completely plausible to have a
> List
> > > of groups and a
> > > List of users and you want to put all of the
> users
> > > into all of the
> > > groups, but does that hold true when you have
> more
> > > than two
> > > references?
> > >
> > > newInstances(documentList, attribute,
> > > elementInstance)
> > > newInstances(document, attributeList,
> > > elementInstance)
> > > newInstances(document, attribute,
> > > elementInstanceList)
> > >
> > > newInstances(document, attributeList,
> > > elementInstanceList)
> > > newInstances(documentList, attribute,
> > > elementInstanceList)
> > >
> > > newInstances(documentList, attributeList,
> > > elementInstance)
> > >
> > > newInstances(documentList, attributeList,
> > > elementInstanceList)
> 
=== message truncated ===



	
		
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