Consider a database of documents in which all documents are kept in a central database. Copies of some documents are kept on mobile computers. Suppose that mobile computer A updates a copy of document 1 while it is disconnected, and, at the same time, mobile computer B updates a copy of document 2 while it is disconnected. Show how the version-vector scheme can ensure proper updating of the central database and mobile computers when a mobile computer reconnects.
Answer to relevant QuestionsGive an example to show that the version-vector scheme does not ensure serializabilityIn the group-commit technique, how many transactions should be part of a group? Explain your answer.Consider a multidatabase system in which it is guaranteed that at most one global transaction is active at any time, and every local site ensures local serializability.a. Suggest ways in which the multidatabase system can ...Consider the data in Exercise 15-2. Use the normal approximation for the sign test to test H0 = 8.5 versus H1 = 8.5, with a = 0.05. What is the P-value for this test?Use the normal approximation to the sign test for the data in Exercise 15-13. With a = 0.05, what conclusions can you draw?
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