[15 Points] Consider an E/R diagram which includes the entity sets F=(c,d), G=(e), and H=(g,h), where the underlined attributes is the keys. In this diagram, there is also a relationship S between G and H, which has f as its own attribute. We also have a weak entity set E=(a,b). Furthermore, G is a subclass of E, that is, the entity set G is connected to E via an isa relationship. Finally, the diagram includes a many-to-one, weak relationship R from E to F, using a rounded arrow to F. Convert this diagram into a relational database schema using each of the following approaches: (1) the E/R style (2) the OO approach (3) the null approach. In each case, show the final relations we get in the database and indicate the keys