What is work of time stamping ?

What is work of timestamping ?

Timestamping is a technique used in concurrency control. Accroding to this technique,  a “timestamp” is assigned to each transaction. And also record the timestamps of transactions that last read and write each database element.

For Example:
Each database element X is associated with
– RT(X): the highest timestamp of a transaction that has read X
– WT(X): the highest timestamp of a transaction that has written X
– c(X): the commit bit of X, which is true iff the most recent transaction to write X has already committed