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Unformatted text preview: Dr. Stefan Brass February 18, 2000 School of Information Sciences University of Pittsburgh INFSCI 2710 “Database Management” — Solution to Example Midterm Exam II — Exercise 1 (ER Design) 12 Points This exercise was a bit difficult because the application is from German canteens/cafeterias for students. The American system is different. I will try to use other examples in future which are better known. Component C Name H H H Recipe Ingredient I Name Calories H H H (0 , * ) H H H H contains H H H H (0 , * ) Quantity J J J t,d Main Dish Side Dish H H H H H H (0 , * ) @ @ @ part of @ @ @ (1 , 1) (0 , * ) @ @ @ part of @ @ @ (0 , * ) Menu M No Q Q Q M Name Price Sales Date Num Sold H H H (0 , * ) H H H H H H H H results in H H H H H H H H You do not need to use subclasses for main dishes and side dishes. If you use an attribute “Type”, you must add a constraint that every Menu contains only one main dish. INFSCI 2710 “Database Management” — Solution to Midterm Exam (Summer 1999) 2 You do not need to use a weak entity for the sales. You could use an entity for Date and put “Num Sold” as an attribute to the relationship “offered on” between Menu and Date....
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