Infinity;Positive infinity

The distinguished valueforever is a special valid-time instant, namely the one following the largest granule in the valid-time domain. Forever is specific to valid time and has no transaction-time semantics.

The valueforever is often used as the valid end time for currently-valid facts. However, this practice is semanticallys incorrect, as such an end time implies that the facts are true during all future times. This usage occurs because database management systems do not offer means of storing the ever-changing current time,now, as an attribute value. To fix the incorrect semantics, the applications that manipulate and query the facts may interpret the semantics specially. However, the better solution is to extend the database management system to support the use of the variablenow as an attribute value.

Concerning the synonyms, “infinity” and “positive infinity” both appear to be more straightforward, but have conflicting...

Authors and Affiliations

1. Aalborg University, Aalborg, Denmark

   Christian S. Jensen

2. University of Arizona, Tucson, AZ, USA

   Richard T. Snodgrass

Editors and Affiliations

1. College of Computing, Georgia Institute of Technology, 266 Ferst Drive, 30332-0765, Atlanta, GA, USA

   LING LIU (Professor) (Professor)

2. Database Research Group David R. Cheriton School of Computer Science, University of Waterloo, 200 University Avenue West, N2L 3G1, Waterloo, ON, Canada

   M. TAMER ÖZSU (Professor and Director, University Research Chair) (Professor and Director, University Research Chair)

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