Question: Which of the relational operators defined in this chapter have
Which of the relational operators defined in this chapter have a definition that does not rely on tuple equality?
Answer to relevant QuestionsGiven the usual suppliers-and-parts database, what is the value of the expression S join Sp join P? What is the corresponding predicate? Warning; there is a trap here.In ordinary arithmetic there are two special numbers, I and 0, with the properties that n * 1 = 1 * n = nAnd n * 0 = 0 * n = 0 for all number n. What relations (if any) play analogous roles in the relational algebra? ...Get all pairs of city names such that a supplier in the first city supplies a project in the second city.Get supplier numbers for suppliers supplying some project with part P1 in a quantity greater than the average shipment quantity of part P1 for that project J1?Show how a system of difference constraints can be solved by a Bellman-Ford-like algorithm that runs on a constraint graph without the extra vertex v0.
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