CH 21: INTRODUCTION TO TRANSACTION PROCESSING CONCEPTS and THEORY #21.14 - Change transaction T 2 in Figure 21.2b to read: read_item(X); X:= X+M; if X > 90 then exit else write_item(X); Discuss the final result of the different schedules in Figure 21.3 (a) and (b), where M = 2 and N = 2, with respect to the following questions. Does adding the above condition change the final outcome? Does the outcome obey the implied consistency rule (that the capacity of X is 90)? #21.18 - How many serial schedules exist for the three transactions in Figure 21.8 (a)? What are they? What is the total number of possible schedules? #21.20 - Why is an explicit transaction end statement needed in SQL but not an explicit begin statement? CH 22: CONCURRENCY CONTROL TECHNIQUES #22.22 - Prove that strict two-phase locking guarantees strict schedules. #22.26 - Repeat Exercise 22.25, but use the multi-version timestamp ordering method. CH 23: DATABASE RECOVERY TECHNIQUES 23.21 - Suppose that the system crashes before the [read_item, T3, A] entry is written to the log in Figure 23.1 (b); will that make any difference in the recovery process? 23.22 - Suppose that the system crashes before the [write_item, T2, D, 25, 26] entry is written to the log in Figure 23.1 (b); will that make any difference in the recovery process? 23.25 - How does checkpointing in ARIES differ from checkpointing as described in Section 23.1.4? 23.27 - What implications would a no-steal/force buffer management policy have on checkpointing and recovery? CH 24: DATABASE SECURITY 24.33 - Suppose that privilege (a) of exercise 24.32 is to be given with GRANT OPTION but only so that account A can grant it to at most five accounts, and each of these accounts can propagate the privilege to other accounts but without the GRANT OPTION privilege. What would the horizontal and vertical propagation limits be in this case? 24.34 - Consider the relation shown in Figure 24.2 (d). How would it appear to a user with classification U? Suppose a classification U user tries to update the salary of "Smith" to $50,000; what would be the result of this action? References: Elmasri, R., & Navathe, S. B. (2011). Fundamentals of Database Systems, 6th ed. New York, NY. Pearson Addison-Wesley