3 votes 3 votes No. Of serial schedules view equal to S S: R1(A), R3(D), W1(B), R2(B), W3(B), R4(B), W2(C), R5(C), W4(E), R5(E), W5(B) . If possible please provide detailed solutions. Thank you in advance Databases transaction-and-concurrency databases view-serializable + – thepeeyoosh asked Jan 6, 2018 thepeeyoosh 3.1k views answer comment Share Follow See all 6 Comments See all 6 6 Comments reply Show 3 previous comments Anu007 commented Jan 7, 2018 reply Follow Share CHECK NOW 0 votes 0 votes Chandrabhan Vishwa 1 commented Oct 29, 2018 reply Follow Share plz any one gives correct method for this 0 votes 0 votes blackcloud commented Nov 8, 2019 reply Follow Share @Anu007 hi! please check for T3..T1..T2..T4..T5 view eqiv rules are maintained as far as i see this... 0 votes 0 votes Please log in or register to add a comment.
3 votes 3 votes LET ME EXPLAIN : LOOK AT DEPENDENCIES : FOR FINAL WRITE B = T5 here condition is (T1, T3)-> T5 E = T4 NO RESTRICTION C = T2 NO RESTRICTION FOR INITIAL READ A= T1 NOT MATTER SINCE NO WRITE ON A D = T3 NOT MATTER SINCE NO WRITE ON D FOR WRITE READ B = T1-> T2 ( NO WRITE COME IN BETWEEN I.E. T3 AND T5) B = T3-> T4 ( NO WRITE COME IN BETWEEN I.E. T1 AND T5) C = T2 -> T5 E= T4-> T5 NOW CONDITIONS : T5 MUST BE LAST T1-> T2 AND T3-> T4 COME ADJACENT ONLY SO T1-> T2-> T3-> T4-> T5 AND T3-> T4->T1->T2-> T5 Anu007 answered Jan 7, 2018 Anu007 comment Share Follow See all 9 Comments See all 9 9 Comments reply thepeeyoosh commented Jan 7, 2018 reply Follow Share When we use T3 --> T2 which generates new updated read (WR)problem. So how can we say it would be view serializable ? 0 votes 0 votes Anu007 commented Jan 7, 2018 reply Follow Share BEFORE T2 READ WE WRITE IT BY T2 SEE T1->T2 SO EFFECT OF T3 IS LOST 0 votes 0 votes thepeeyoosh commented Jan 7, 2018 reply Follow Share Which of following is the Problem for data item B 0 votes 0 votes Anu007 commented Jan 7, 2018 reply Follow Share IN VIEW SERIAL ONLY LAST WRITE MATTER SO T3 -> T5 NO ISSUE. SAME T3->T1 NO ISSUE YOU ARE CHECKING CONFLICT SERIALIZABLE. 0 votes 0 votes thepeeyoosh commented Jan 7, 2018 reply Follow Share That's means conflict problem (WW, WR RW for same data item) is not same as view problem or serializable problem ? 0 votes 0 votes Anu007 commented Jan 7, 2018 reply Follow Share YES SOME RESTRICTION ARE REMOVED FROM VIEW , IN COMPARISION TO CONFLICT. LIKE WW. 0 votes 0 votes thepeeyoosh commented Jan 7, 2018 reply Follow Share For above image all are conflict pairs? 0 votes 0 votes thepeeyoosh commented Jan 7, 2018 reply Follow Share Is is true or not? (RW , WR conflict pair is same precedence for two schedule S and S') iff (intial read and updated read same for S and S') But only implication for (WW conflict pair) --> (final write) 0 votes 0 votes Kiran Karwa commented Jan 8, 2018 reply Follow Share @ Anu007 If No. Of serial schedules conflict equal to S was asked then just this one right, T1-> T2-> T3-> T4-> T5 0 votes 0 votes Please log in or register to add a comment.