10 - Temporal Transactions on Single Tables

Abstract

This chapter presents a discussion on the maintenance of individual asserted version tables, with focus on temporal entity integrity (TEI). TEI checks insure that, at any given moment of assertion time or during any given period of assertion time, no object may be represented in an effective time clock tick more than once. TEI applies to both episodes and to versions within episodes. For episodes, it is the constraint that no two episodes of the same object, in the same period of assertion time, either are contiguous with one another or share even a single clock tick. Using the terminology from Allen relationship taxonomy, it is the constraint that no two episodes of the same object, in the same period of assertion time, either [meet] or [intersect]. They share no clock ticks, and they all have at least one unoccupied clock tick between them. One is always [before] the other. For versions within an episode, temporal entity integrity is the constraint that each effective-time adjacent pair of versions [meet] but do not [intersect]. They share no clock ticks, and have no unoccupied clock ticks between them. There are two ways of demonstrating completeness of temporal transactions, including Allen relationship check, and temporal extent transformation completeness check.