Modeling Time in REA/Real Databases: Planning and Availability
24 Pages Posted: 29 Dec 2013
Date Written: July 27, 1999
Modeling time to meet enterprise requirements in REA requires two orthogonal concepts: valid time and transaction time. Valid time can be multidimensional, including historical, planned and plan instantiation time. Transaction time is when the information is recorded.
Valid time is proposed as an addition to the REA model for each of resources, events and agents. Transaction time can be associated with each REA tuple. Transaction time can be particularly critical from a control perspective, e.g., providing information for intrusion detection systems, and performance monitoring perspective, providing information that can be used to measure efficiency. In addition, given transaction time, the database can be “rolled-back” to the world as of some previous time.
Historical valid time-based information can be captured to allow determination of resource, agent and location availability for planning. Valid time can also be used to capture time for events using either a single dimensional historical view or a multidimensional one that accounts for an enterprise planning model of time. This allows capture of planning event information, and linkage in a dual relationship to actual plan instantiation of planning events. Sequentially, generally, availability time proceeds planned usage time, which proceeds plan instantiation time.
The planning event, along with the resources and agents, becomes the initiated basis of analysis, and provides an alternative type of “duality.”
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