|
Archive@NYU >
Stern School of Business >
IOMS: Information Systems Working Papers >
Please use this identifier to cite or link to this item:
http://hdl.handle.net/2451/14356
|
| Title: | ON THE SEMANTICS OF TRANSACTION TIME AND VALID TIME IN BITEMPORAL DATABASES |
| Authors: | Clifford, James
Isakowitz, Tomas |
| Issue Date: | 23-Dec-1992 |
| Publisher: | Stern School of Business, New York University |
| Series/Report no.: | IS-92-42 |
| Abstract: | Numerous proposals for extending the relational data model to
incorporate the temporal dimension of data have appeared in the past
several years. While most of these have been historical databases,
incorporating in some fashion a valid time dimension to the data model
and the query languages, others have been rollback databases,
incorporating a transaction time dimension, or bitemporal databases,
incorporating both of these temporal dimensions. In this paper we
address an issue that has been lacking in many of these papers, namely,
a formal specification of the precise semantics of these temporal
dimensions of data. We introduce the notion of reference time - the time
that any operation is applied to the database state - and provide a
logical analysis of the interrelationships among these three temporal
dimensions. We also provide an analysis of the meaning of various
variables such as now and â which have been used in many of
these models without a complete specification of their semantics. |
| URI: | http://hdl.handle.net/2451/14356 |
| Appears in Collections: | IOMS: Information Systems Working Papers
|
All items in Faculty Digital Archive are protected by copyright, with all rights reserved.
|
