Design a generalization–specialization hierarchy for a motor-vehicle sales company. The company sells motorcycles, passenger cars, vans, and buses. Justify your placement of attributes at each level of the hierarchy. Explain why they should not be placed at a higher or lower level.
Answer to relevant QuestionsExplain the distinction between condition-defined and user-defined constraints. Which of these constraints can the system check automatically? Explain your answer.Consider two separate banks that decide to merge. Assume that both banks use exactly the same E-R database schema—the one in Figure below (This assumption is of course highly unrealistic; we consider the more realistic ...Consider the relation of as shown below, which shows the result of the query “Find the names of all customers who have a loan at the bank.” Rewrite the query to include not only the name, but also the city of residence ...Let R = (A, B, C), and let r1 and r2 both be relations on schema R. Give an expression in the domain relational calculus that is equivalent to each of the following: a. IIA(r1) b. σB =17 (r1) c. r1 ∪ r2 d. r1 ...Let the following relation schemas be given: R = (A, B, C) S = (D, E, F) Let relations r(R) and s(S) be given. Give an expression in SQL that is equivalent to each of the following queries. a. п A(r) b. σB = ...
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