Hi all

I'm trying to figure out how to map my data requirements to objects. I have a typical parent/child database where (eg) a Site object would be the parent to all the User and Notice (family announcement) objects in that website:

That's fine, because each User and Notice object is unique in the DB. All objects which live in the database inherit from DBObject, which provides ORM functionality.

But now, I want to add Charities, classified by Category. So I have a Charity::Category object, which can be parent to other Charity::Category objects. But the charities themselves can appear in more than one category, so I have written a Set class, which sub-classes DBObject, to provide set membership.

All well and good. I can ask for Charity::Category->members and get all the Charities in that category

So now I'm thinking... Notices can have Images, Comments, Editors, and Charities. What is the best way to implement this? I see two options:

1. Notice is parent to CharityList, ImageList, CommentList, EditorList, and each of these objects inherit from Set, and contain just one class of object (ie just Charities, or just Images):

     Notice: 123
       - CharityList : 124 (members: Charity1, Charity2)
       - ImageList : 125 (members: Image1, Image2)
     etc
   [download]

   so I could say :

   @charities = $notice->charity_list->members

   Disadvantage : I have to create a number of different classes, and I think it would be more DB intensive

2. Notice itself sub-classes Set, and contains any class of object in its membership list:

   
     Notice: 123 (members: Charity1, Charity2, Image1, Image2)
     etc
   [download]

   and I can say:

   @charities = $notice->members({type => 'charity'})

   Disadvantage : Sets cache their membership lists, and so I would need to cache different types of lists (eg {type => 'Charity'}, {type => 'Charity', status => 'active'}), etc, which would make it trickier.,

Which is the cleaner, more OO solution? (Have I explained my question sufficiently?)

thanks

Clint

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