Transaction time a concept originated by Richard T. Snodgrass

Richard T. Snodgrass

Richard Thomas Snodgrass is an American computer scientist and writer, currently employed as a professor at the University of Arizona. He is best known for his work on temporal databases, query language design, query optimization and evaluation, storage structures, database design, and ergalics...

 and his doctoral student, is used in temporal database

Temporal database

A temporal database is a database with built-in time aspects, for example a temporal data model and a temporal version of Structured Query Language.More specifically the temporal aspects usually include valid-time and transaction-time...

s. It denotes the time period during which a database fact is/was stored in the database.

In a database table transaction time is often represented by two extra table-columns StartTT and EndTT. The time interval is closed at its lower bound and open at its upper bound

Upper bound

In mathematics, especially in order theory, an upper bound of a subset S of some partially ordered set is an element of P which is greater than or equal to every element of S. The term lower bound is defined dually as an element of P which is lesser than or equal to every element of S...

.

When the ending transaction time is unknown, it may be considered as "Until Closed". Academic researchers and some RDBMS have represented "Until Closed" with the largest timestamp supported or the keyword "forever". This convention is not technically precise.