Dealing with granularity of time in temporal databases
CAiSE '91 Proceedings of the third international conference on Advanced information systems engineering
Understanding the new SQL: a complete guide
Understanding the new SQL: a complete guide
A glossary of temporal database concepts
ACM SIGMOD Record
Timestamp semantics and representation
Information Systems
ATOM: a system for building customized program analysis tools
PLDI '94 Proceedings of the ACM SIGPLAN 1994 conference on Programming language design and implementation
Efficient timestamp input and output
Software—Practice & Experience
Temporal modules: an approach toward federated temporal databases
Information Sciences—Informatics and Computer Science: An International Journal
The avatars of a package for calendars in Ada
Software—Practice & Experience
Algebraic query languages on temporal databases with multiple time granularities
CIKM '95 Proceedings of the fourth international conference on Information and knowledge management
Building the data warehouse (2nd ed.)
Building the data warehouse (2nd ed.)
Calendrical calculations
Modeling temporal primitives: back to basics
CIKM '97 Proceedings of the sixth international conference on Information and knowledge management
Supporting valid-time indeterminacy
ACM Transactions on Database Systems (TODS)
Time modeling in office information systems
SIGMOD '85 Proceedings of the 1985 ACM SIGMOD international conference on Management of data
Time concept in generalized data bases: TIGRE project
ACM '85 Proceedings of the 1985 ACM annual conference on The range of computing : mid-80's perspective: mid-80's perspective
Maintaining knowledge about temporal intervals
Communications of the ACM
The TSQL2 Temporal Query Language
The TSQL2 Temporal Query Language
DBMS Support for Nonmetric Measurement Systems
IEEE Transactions on Knowledge and Data Engineering
Integrating Calendar Dates and Qualitative Temporal Constraints in the Treatment of Periodic Events
IEEE Transactions on Knowledge and Data Engineering
Implementing Calendars and Temporal Rules in Next Generation Databases
Proceedings of the Tenth International Conference on Data Engineering
An Algebraic Representation of Calendars
Annals of Mathematics and Artificial Intelligence
Supporting User-Defined Granularities in a Spatiotemporal Conceptual Model
Annals of Mathematics and Artificial Intelligence
Capturing Delays and Valid Times in Data Warehouses—Towards Timely Consistent Analyses
Journal of Intelligent Information Systems - Special issue on data warehousing and knowledge discovery
Symbolic User-Defined Periodicity in Temporal Relational Databases
IEEE Transactions on Knowledge and Data Engineering
Managing Time Consistency for Active Data Warehouse Environments
DaWaK '01 Proceedings of the Third International Conference on Data Warehousing and Knowledge Discovery
Temporal coalescing with now granularity, and incomplete information
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
Event choice datalog: a logic programming language for reasoning in multiple dimensions
PPDP '04 Proceedings of the 6th ACM SIGPLAN international conference on Principles and practice of declarative programming
Augmenting a Conceptual Model with Geospatiotemporal Annotations
IEEE Transactions on Knowledge and Data Engineering
Spatiotemporal Aggregate Computation: A Survey
IEEE Transactions on Knowledge and Data Engineering
An efficient method for temporal aggregation with range-condition attributes
Information Sciences—Informatics and Computer Science: An International Journal
Temporal reasoning for decision support in medicine
Artificial Intelligence in Medicine
Compact and tractable automaton-based representations of time granularities
Theoretical Computer Science
Mining fuzzy periodic association rules
Data & Knowledge Engineering
Multigranular spatio-temporal models: implementation challenges
Proceedings of the 16th ACM SIGSPATIAL international conference on Advances in geographic information systems
"Same, Same but Different" A Survey on Duplicate Detection Methods for Situation Awareness
OTM '09 Proceedings of the Confederated International Conferences, CoopIS, DOA, IS, and ODBASE 2009 on On the Move to Meaningful Internet Systems: Part II
Modeling Concept Evolution: A Historical Perspective
ER '09 Proceedings of the 28th International Conference on Conceptual Modeling
GeTS: a specification language for geo-temporal notions
KI'06 Proceedings of the 29th annual German conference on Artificial intelligence
Multi-granular spatio-temporal object models: concepts and research directions
ICOODB'09 Proceedings of the Second international conference on Object databases
Journal of Systems and Software
Modeling Spatial and Temporal Set-Based Constraints During Conceptual Database Design
Information Systems Research
International Journal of Mobile Computing and Multimedia Communications
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Granularity is an integral feature of temporal data. For instance, a person's age is commonly given to the granularity of years and the time of their next airline flight to the granularity of minutes. A granularity creates a discrete image, in terms of granules, of a (possibly continuous) time-line. We present a formal model for granularity in temporal operations that is integrated with temporal indeterminacy, or 驴don't know when驴 information. We also minimally extend the syntax and semantics of SQL-92 to support mixed granularities. This support rests on two operations, scale and cast, that move times between granularities, e.g., from days to months. We demonstrate that our solution is practical by showing how granularities can be specified in a modular fashion, and by outlining a time- and space-efficient implementation. The implementation uses several optimization strategies to mitigate the expense of accommodating multiple granularities.