Computer
The temporal query language TQuel
ACM Transactions on Database Systems (TODS)
The R*-tree: an efficient and robust access method for points and rectangles
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
On the semantics of “now” in databases
ACM Transactions on Database Systems (TODS)
On the analysis of indexing schemes
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
An extensible notation for spatiotemporal index queries
ACM SIGMOD Record
Multidimensional access methods
ACM Computing Surveys (CSUR)
Comparison of access methods for time-evolving data
ACM Computing Surveys (CSUR)
SQL:1999: understanding relational language components
SQL:1999: understanding relational language components
The TSQL2 Temporal Query Language
The TSQL2 Temporal Query Language
Designing Access Methods for Bitemporal Databases
IEEE Transactions on Knowledge and Data Engineering
IEEE Transactions on Knowledge and Data Engineering
R-Tree Based Indexing of Now-Relative Bitemporal Data
VLDB '98 Proceedings of the 24rd International Conference on Very Large Data Bases
Interval Processing with the UB-Tree
IDEAS '02 Proceedings of the 2002 International Symposium on Database Engineering & Applications
Layered Temporal DBMS: Concepts and Techniques
Proceedings of the Fifth International Conference on Database Systems for Advanced Applications (DASFAA)
Access Methods for Bi-Temporal Databases
Proceedings of the International Workshop on Temporal Databases: Recent Advances in Temporal Databases
Light-Weight Indexing of General Bitemporal Data
SSDBM '00 Proceedings of the 12th International Conference on Scientific and Statistical Database Management
The Official Guide to DB2 Version 8
The Official Guide to DB2 Version 8
Temporal Data and the Relational Model
Temporal Data and the Relational Model
An efficient method for indexing now-relative bitemporal data
ADC '04 Proceedings of the 15th Australasian database conference - Volume 27
BiB+-tree: an efficient multiversion access method for bitemporal databases
Proceedings of the 11th International Conference on Information Integration and Web-based Applications & Services
Journal of Intelligent Information Systems
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Most modern database applications involve a significant amount of time dependent data and a significant portion of this data is now-relative. Now-relative data are a natural and meaningful part of every temporal database as well as being the focus of most queries. Previous studies indicate that the choice of the representation of now significantly influences the efficiency of accessing bitemporal data. In this paper we propose and experimentally evaluate a novel approach to represent now that we termed the POINT approach, in which now-relative facts are represented as points on the transaction-time and/or valid-time line. Furthermore, in the POINT approach we propose a logical query transformation that relies on the above representation and on the geometry features of spatial access methods. Such a logical query transformation enables off-the-shelf spatial indexes to be used. We empirically prove that the POINT approach is efficient on now-relative bitemporal data, outperforming the maximum timestamp approach that has been proven to the best approach to now-relative data in the literature, independently of the indexing methodology (B 驴+驴- tree vs R *- tree) being used. Specifically, if spatial indexing is used, the POINT approach outperforms the maximum timestamp approach to the extent of factor more than 10, both in number of disk accesses and CPU usage.