Ace Test Series: Databases - Transactions

Question

Whether the given schedule is conflict serializable or view serializable or none.

Comments

In your last link, in all the examples, the commit statements are at the last. So those are not good counter examples.

See this. Explained. https://gateoverflow.in/100871/precedence-graph

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I understand. But if possible can you give some reason why this happens? I mean if you consider the given question it does actually matter whether Write A of T2 is after read of T1 or not. Do you have any idea about why introduction of commit changes things?

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@asdfghjk I am not aware of the reason. Sorry!!

Answer 1

View Serialzble

Comments

How this is view serializable. t2 is dependent on t1 since intial read is performed by t1 , but t2 commits before t1.

Answer 2

there is no cycle is precedence graph of this schedule , hence it is conflict serializable.

but every conflict is also view serializable . therefor OPTION – C