Which one of the following statements describes why the UML Class diagram is a superset of the E-R diagram? a) Class diagrams model abstractions. b) Class diagrams model behavior as well as data. c) Class diagrams may be refined into a physical mplementation. d) Class diagrams model many to many relationships. e) Class diagrams show relationships between data elements. Answer pls? Ramdhan YK
Ram Dhan Yadav (SCJP, SCWCD, SCJA-I, IBM EC(483))
"We are what we repeatedly do. Excellence, then, is not an act, but a habit."
My answer is E! E-R diagrams show relationships between data elements. I believe E-R diagrams do not model behaviour. All you do is organize entities (and their attributes) and build relationships (identifying, non-identifying, one-to-one, One-to-many etc) to normalize the entities.
i am unable to understand that why most of saying e.although q's is about superset. if e is the answer then how uml class diagram can be superset of er . i think b can be the answer. if i am wrong then plz refine me. ------------------
b) has highest probability < !Entity supersetSubset <br /> "But that does not describe superset-subset relationship."> (replace &supersetSubset; with the String. Thats the way internal general entities work in xml.)
a) both model abstractions. &supersetSubset; b) e-r diagrams model data. class diagrams model data as well as behaviour. So its a superset. c) both might be refined in a physical implementation. &supersetSubset;
d) with class diagramms as well as with e-r diagramms you can model many to many relationsships. &supersetSubset; e) class diagrams as well e-r diagrams show relationship between data. &supersetSubset;