Give an example of an expression defining a materialized view and two situations (sets of statistics for the input relations and the differentials) such that incremental view maintenance is better than recomputation in one situation and recomputation is better in the other situation.
Answer to relevant QuestionsList the ACID properties. Explain the usefulness of each. Justify the following statement: Concurrent execution of transactions is more important when data must be fetched from (slow) disk or when transactions are long, and is less important when data is in memory and transactions ...Consider the following two transactions:T31: read (A); read (B);If A = 0 then B: = B + 1; write (B).T32: read (B); read (A);If B = 0 then A: = A + 1; write (A).Add lock and unlock instructions to transactions T31 and T32, so ...Consider the following graph-based locking protocol that allows only exclusive lock modes, and that operates on data graphs that are in the form of a rooted directed acyclic graph.• A transaction can lock any vertex ...Show that there are schedules that are possible under the two-phase locking protocol, but are not possible under the timestamp protocol, and vice versa.
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