Mention different types of Security levels.

Find the Super Keys : R(ABCDE) FDs : AB -> C, C->D, B->E

If we have database, then how can we tell the data in the “database is secured”. Also what is meant by “data validation”

Check whether the given schedules are conflict serializable or not S1 : R2(B)W2(A)R1(A)R3(A)W1(B)W2(B)W3(B) S2:R3(Y)W3(Z)R1(X)W1(X)W3(Y)W3(Z)R2(Z)R1(Y)W1(Y)R2(Y)W2(Y)

IF the system recovers from a crash, it constructs an undo-list and a redo-list. Explain why log records for transactions on the undo-list must be processed in reverse order while those log records for transactions on the redo-list are processed ...

Consider the following transactions with data items P and Q initialized to zero: T1 : read (P) ; read (Q) ; if P = 0 then Q : = Q + 1 ; write (Q). T2 : read (Q) ; read (P) if Q = 0 then ...