[citation needed] It is used to keep a history of decisions about valid times.
In a database table, the start and end time of the decision time interval can be represented by adding two table columns.
[2] The term decision time was coined by Mario Nascimento and Margaret Eich (1995).
The following is a list of real events that occurred between the 1964 and 1976 United States presidential elections: In this example, a constant 7-day delay is assumed between the decision time and the transaction time when the data is committed to the database.
Given those conditions, the database would have contained the following information after the election in 1976: Given the 7-day delayed table above, the question "who was president and vice president for the valid time of 1977-01-01" (which given the 7-day delay could provide data for 1976-12-25) would be: