Database Design - Name for this convention?

I am trying to figure out a good way to handle the following scenario in Entity Framework, but do not know the name for the convention used, so I'm having a difficult time finding results:

The Base Tables

Category Table: CategoryID, Name, ..., Active

Webpage Table: WebpageID, Name, ..., Active

Product Table: ProductID, Name, ..., Active

Link Table: LinkID, Name, ..., Active

The Relation Table

Relationships Table: ID, CategoryID, ChildID, ChildTypeID, SortOrder

(ChildID can be CategoryID, WebpageID, ProductID, or LinkID. ChildTypeID identifies which table/type the ChildID is linked too)

What should I be using for search terms to find information on this type of relationship? Does anyone have any links to resources that might be useful in handling this sort of thing in Entity Framework? I'm contemplating breaking the Relationships t开发者_高级运维able out into four tables, but would like to make sure I'm not creating more work for myself than is necessary.

In Hibernate it would be called Inheritance Mapping. Try searching Entity Framework documentation for similar terms.