Valid time

In temporal databases, valid time (VT) is the time period during which a database fact is valid in the modeled reality. As of December 2011, ISO/IEC 9075, Database Language SQL:2011 Part 2: SQL/Foundation included clauses in table definitions to define 'application-time period tables' (that is, valid-time tables). Valid time was coined by Richard T. Snodgrass and his doctoral student. In temporal databases, valid time (VT) is the time period during which a database fact is valid in the modeled reality. As of December 2011, ISO/IEC 9075, Database Language SQL:2011 Part 2: SQL/Foundation included clauses in table definitions to define 'application-time period tables' (that is, valid-time tables). Valid time was coined by Richard T. Snodgrass and his doctoral student. In a database table valid time is often represented by two extra table-columns StartVT and EndVT. The time interval is closed at its lower bound and open at its upper bound.