Paul, My first question would be - how do you actually benefit from having this data separated? Is there a reason that you don't just create a new entity for the new project that can represent the entire organization?
If the reason is that you have code that you would typically use in more than one project, I would consider building that into POJOs . In general, I find that the benefits of splitting up entities (either through inheritance OR composition) seldom outweighs the benefits of having them together, unless there are some circumstances that totally warrant it. If you could provide more information on the perceived benefits, people might be able to help you better. Ken On May 29, 2012, at 1:16 AM, Paul Hoadley wrote: > Hello, > > I'm after some general modelling advice. I've been using inheritance for > years to model app-specific versions of a framework-level Person (user) > entity. This works well enough, though it presents the same small headaches > time after time for each new application. > > I also have a framework-level Organisation entity to model a user's > organisation. I need to customise this for a new application, and I thought > this time I would use composition instead of inheritance—I'll create a new > FooOrganisation entity which has a to-one relationship to Organisation > (without the inverse relationship), and then the additional attributes and/or > relationships which are app-specific. > > The application is still in development, but there's a demo deployment, and > while I _can_ wipe the database, there are existing Organisation EOs in it, > and it would be nice if I didn't have to. I'm using migrations, so I can > perform any one-off fix-ups in a post-migration step. > > So, do people model like this? Are there any pitfalls? What's the best way > to ensure referential integrity, such that Organisation and FooOrganisation > remain 1-1—'owns destination' and 'propagates primary key'? (Selecting those > will require I scrap the DB and create the FooOrganisations first, won't it?) > Would dynamically adding some properties to the model at runtime be a better > option here if I just want to store, say, a few limited extra attributes on > an entity? > > > -- > Paul Hoadley > http://logicsquad.net/ > > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/webobjects-dev/kenlists%40anderhome.com > > This email sent to kenli...@anderhome.com
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