5 ms·

Then how would subtype polymorphism work?

• scotty79 8y ago
  If you just want to inherit from the object collection you already have to have new object collection that behaves slightly differently then it should work exactly the same way as usual. If you wanted to have different types of objects in one collection first you'd have to ask yourself if you really need to keep them together. But if so I suppose you'd just put base fields in one collection and new additional fields in another. Then handle to derived object would consist of two indexes, one in the base collection and the other in the collection of additional fields. Methods that access base field would need to use first index for them, and second index for additional fields. Not sure if I'm being clear enough. Imagine you want to store collection of various subtyped objects in the database. This is pretty much the same problem. You keep base fields in one table, and specific fields in other tables (one for each subtype), and if you want to operate just on base fields you use base table, but if you want to operate on fields specific for a subtype you join base table with table that contains fields specific for that subtype.