On the finite and general implication problems of independence atoms and keys
TLDR
It is shown that the general implication of keys and unary independence atoms and of unary keys and general independence atoms is decidable in polynomial time, and tractable conditions that are sufficient for certain classes of Keys and independence atoms not to interact are established.About:
This article is published in Journal of Computer and System Sciences.The article was published on 2016-08-01 and is currently open access. It has received 23 citations till now. The article focuses on the topics: Unary function & Unary operation.read more
Citations
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Possible and certain keys for SQL
TL;DR: This work revisits the fundamental notion of a key in relational databases with NULL and investigates the notions of possible and certain keys, which are keys that hold in some or all possible worlds that originate from an SQL table, respectively.
Journal ArticleDOI
Approximation and dependence via multiteam semantics
TL;DR: This work defines natural probabilistic versions of inclusion and independence atoms and certain approximation operators motivated by approximate dependence atoms of Väänänen in a variant of team semantics based on multisets.
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Complexity of Propositional Logics in Team Semantic
TL;DR: The main result shows that the satisfiability and validity problems for propositional team logic are complete for alternating exponential-time with polynomially many alternations.
Book ChapterDOI
Probabilistic Team Semantics
TL;DR: This article studies a variant of probabilistic team semantics and relates this framework to a Tarskian two-sorted logic and shows that very simple quantifier-free formulae of this logic give rise to hard model checking problems.
References
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Multivalued dependencies and a new normal form for relational databases
TL;DR: It is shown that every relation schema can be decomposed into a family of relation schemata in fourth normal form without loss of information (that is, the original relation can be obtained from the new relations by taking joins).
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Testing implications of data dependencies
TL;DR: The chase operates on tableaux similar to those of Aho, Sagiv, and Ullman so it is possible to test implication of join dependencies and functional dependencies by a set of dependencies.
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Building a high-level dataflow system on top of Map-Reduce: the Pig experience
Alan Gates,Olga Natkovich,Shubham Chopra,Pradeep Kamath,Shravan Narayanamurthy,Christopher Olston,Benjamin Reed,Santhosh Srinivasan,Utkarsh Srivastava +8 more
TL;DR: Pig is a high-level dataflow system that aims at a sweet spot between SQL and Map-Reduce, and performance comparisons between Pig execution and raw Map- Reduce execution are reported.
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Horn clauses and database dependencies
TL;DR: A new concept is mtroduced, called "faithfulness (with respect to direct product)," which enables powerful results to be proved about the existence of "Armstrong relations" in the presence of these new dependencies.