منابع مشابه
Aggregates in the Temporal Query Language TQuel
TR 8E-009 This paper defines aggregates in the temporal query language TQuel and provides their rormal semantics in the tuple relational calculus. A rormal semantics (or Que! aggregates is defined in the process. Multiple aggregates; aggregates appearing in the where, when, valid, and as-or clauses; nested aggregation; and instantaneous, cumulative, and unique variants are supported. These aggr...
متن کاملAggregates in the temporal query language TQuel - Knowledge and Data Engineering, IEEE Transactions on
This paper defines new constructs to support aggregation in the temporal query language TQuel and presents their formal semantics in the tuple relational calculus. A formal semantics for Que1 aggregates is defined in the process. Multiple aggregates; aggregates appearing in the where, when, and valid clauses; nested aggregation; and instantaneous, cumulative, moving window, and unique variants ...
متن کاملTVQL - Temporal Versioned Query Language
The Temporal Versions Model (TVM) is an Object Oriented Data Model developed to store the object versions and, for each version, the history of its dynamic attributes and relationships values. In this work, we propose a query language for this model. The language, called Temporal Versioned Query Language TVQL, is based on SQL, adding new features to recover temporal information and versions. An...
متن کاملA Visual Query Language for Temporal Databases a Visual Query Language for Temporal Databases
This paper addresses the issue of visual query formulation for temporal databases. We introduce a number of visual constructs that allow users to build queries in a modular, bottom{up fashion based on a temporal Extended Entity{Relationship Model. These constructs are: Temporal projection, temporal selection, time links, ltering and set operators, and temporal aggregates. This paper also identi...
متن کاملThe Expressive Power of the Temporal Query Language Lh
Temporal knowledge representation and reasoning methods require expressive power — which ensures usefulness in non-trivial applications as well as reasonable complexity, which guarantees efficient implementation. The temporal language LH [7, 4, 8, 5] is an attempt to find a balance between expressive power and complexity. LH serves as a means for expressing temporal constraints over the propert...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: ACM Transactions on Database Systems
سال: 1987
ISSN: 0362-5915,1557-4644
DOI: 10.1145/22952.22956