Question: We have seen that data definition operations cause updates to
We have seen that data definition operations cause updates to be made to the catalog. But the catalog is only a collection of relvars, just like the rest of the database; so could we not use the regular update operations insert. Delete, and update to update the catalog appropriately? Discuss.
Answer to relevant QuestionsIn the body of the chapter, we said that any type whatsoever can be used as the basis for defining relational attributes, in general. That qualifier “in general” was there for a reason, however. Can you think of any ...Let r be a relation of degree n. How many different projections of r are there?Let r be the relation denoted by the following expression; SP group () as x Show what r looks like, given our usual sample value for SP. Also, show the result of; r ungroup xGet the total number of part P1 supplied by supplier S1Get all pairs of supplier numbers, Sx and Su say, such that Sx and Sy supply exactly the same set of parts each. Note for simplicity, you might want to use the original suppliers-and-parts data-base for this exercise, ...
Post your question