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What's the definition of timestamp?
The timestamp is just for a transaction? ( no matter what actions in the transaction. The timestamp is always the time when the transaction happened.)
OR the timestamp is for each action of a transaction? (each action has a timestamp.)

T1 | R1(x)                         R1(X)
T2 |       R2(Y) R2(Y) W2(X)
T3 |                         W3(Y)

For instance, when first R1(X) happened, it has a timestamp TS. But for the second R1(X), the timestamp is same with the TS? OR the timestamp has changed?

For another example, if I have R1(X)W2(X)W1(X), is it view serializable? and is it conflict serializable?

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Timestamp in which RDBMS? And please remove the   strings from your question. You can format your table as code (with the {} button above), so you will have a fixed with font and easy table formatting. If you need help in this, please tell. –  dezso Dec 16 '12 at 15:57
@dezso thx, but I don't know how to make a table. Please help. thx. –  meshuai Dec 16 '12 at 16:12
Done. Is this what you wanted to see? –  dezso Dec 16 '12 at 16:22
@dezso yes. thx. learn more. –  meshuai Dec 16 '12 at 16:28
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