Could you help me understand why the schedule on the picture is view serializable without any "blind write"?
Also, should the results be the same if two schedules are view equivalent?
I did create serial version of the schedule and compare but they do not seem view equivalent to each other.
Could you tell me if a concurrent schedule is view serializable, would it and a serial version of it have the same result in the end?
Me and my lecturer have different opinions, and it is very hard for me to understand hers. She thinks it is view serializable but I do not. I am not sure who is correct.
If two schedules are view equivalent to each other, they are called as being view serializable.
- Initial Read If a transaction T1 reading data item A from initial database in S1 then in S2 also T1 should read A from initial database.
- Updated Read If Ti is reading A which is updated by Tj in S1 then in S2 also Ti should read A which is updated by Tj.
- Final Write operation If a transaction T1 updated A at last in S1, then in S2 also T1 should perform final write operations.
If this three conditions are satisfied, these two schedule are called view equivalent to each other.