On conjunctive queries containing inequalities
Journal of the ACM (JACM)
Evaluation of relational algebras incorporating the time dimension in databases
ACM Computing Surveys (CSUR)
Selected papers of the 9th annual ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
On the semantics of “now” in databases
ACM Transactions on Database Systems (TODS)
The complexity of querying indefinite data about linearly ordered domains
Journal of Computer and System Sciences - Special issue: dedicated to the memory of Paris Kanellakis
Advanced database systems
On the containment and equivalence of database queries with linear constraints (extended abstract)
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
The TSQL2 Temporal Query Language
The TSQL2 Temporal Query Language
Principles of Database and Knowledge-Base Systems: Volume II: The New Technologies
Principles of Database and Knowledge-Base Systems: Volume II: The New Technologies
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
SQL Extension for Interval Data
IEEE Transactions on Knowledge and Data Engineering
Point-Based Temporal Extension of Temporal SQL
DOOD '97 Proceedings of the 5th International Conference on Deductive and Object-Oriented Databases
Coalescing in Temporal Databases
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
A complete temporal relational algebra
The VLDB Journal — The International Journal on Very Large Data Bases
TIME '01 Proceedings of the Eighth International Symposium on Temporal Representation and Reasoning (TIME'01)
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Tuples of a temporal relation are equipped with a valid time period. A simple extension of the selection-projection-cross product (SPC) algebra for temporal relations is defined, which conforms to primitives in existing temporal query languages. In particular, temporal projection involves coalescing of time intervals, which results in non-monotonic queries. Also the "select-from-where" normal form is no longer available in this temporal extension. In view of these temporal peculiarities, it is natural and significant to ask whether query optimization techniques for the SPC algebra still apply in the temporal case. To this extent, we provide a temporal extension of the classical tableau formalism, and show its use and limits for temporal query optimization.