In computer science

Computer science

Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...

, particularly the field of database

Database

A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

s, the Thomas Write rule is a rule in timestamp-based concurrency control

Timestamp-based concurrency control

In computer science, in the field of databases, timestamp-based concurrency control is a non-lock concurrency control method, used in relational databases to safely handle transactions, using timestamps.-Assumptions:...

.

It states that, if a more recent transaction has already written the value of an object, then a less recent transaction does not need to have written its change.

For example:


Assuming that the timestamp of T1 is less than that of T2, T1's write is discarded.