19.Assume you are dealing with a purchasing database involving a single table. This table contains information on the customer, sale, and items purchased; the sales order number is the primary key. Using this database design, as you remove old sales information, you may lose information on some of your customers. This is an example ofA. a hidden dependencyB. a deletion anomolyC. an update anomolyD. an insertion anomoly20.Which of the following is true about the following BOOK dependency diagram where ISBN is the primary key?21.Which of the following is true about a simple primary key?
22.An attribute that must have a value for every entity (or relationship) instance is a(n):23. A student can attend five classes, each with a different professor. Each professor has 30 students. The relationship of students to professors is a _________ relationshipA. one-to-oneB. one-to-manyC. many-to-manyC. strong24.Which of the following is true about supertype, subtype structure?A. Relationship at the supertype level indicate that all subtypes will participate in the relationshipB. Subtype entities inherit values of all attribute of the supertypeC. An instance of a subtype is also an instance of the supertypeD. all of the above25.In the figure below, what is true about the attributes ItemNo and ComponentNo?26.The attribute on the left-hand side of the arrow in a functional dependency is a A. primary keyB. determinantB. non-keyC. none of the above27.A functional dependency of the form Student# Advisor Advisor_Office is called a:
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- d., Relational model, primary key, MIDTERM EXAM FALL 2018, A. SNUM