19,259 Hits in 4.1 sec

Task-Oriented Complex Ontology Alignment: Two Alignment Evaluation Sets [chapter]

Élodie Thiéblin, Ollivier Haemmerlé, Nathalie Hernandez, Cassia Trojahn
2018 Lecture Notes in Computer Science  
The ontology merging alignment set contains 313 correspondences and the query rewriting one 431. We report an evaluation of state-of-the art complex matchers on the proposed alignment sets.  ...  The methodology for creating the alignment sets is described and takes into account the use of the alignments for two tasks: ontology merging and query rewriting.  ...  The query rewriting set is composed of 431 correspondences with 191 complex correspondences from 17 different patterns (some patterns are composite).  ... 
doi:10.1007/978-3-319-93417-4_42 fatcat:cxwx4ehtozbejigfhieunpxd5e


Konstantinos Makris, Nikos Bikakis, Nektarios Gioldasis, Stavros Christodoulakis
2012 Proceedings of the 15th International Conference on Extending Database Technology - EDBT '12  
The SPARQL-RW provides a generic method for SPARQL query rewriting, with respect to a set of predefined mappings between ontology schemas.  ...  This paper presents SPARQL-RW (SPARQL-ReWriting), a framework which provides transparent query access over mapped RDF datasets.  ...  over their corresponding data and observe the query rewriting process via an interactive user interface.  ... 
doi:10.1145/2247596.2247678 dblp:conf/edbt/MakrisBGC12 fatcat:ytqddqjuqzg5doc7bp4uvvgzma

Efficient XQuery rewriting using multiple views

Ioana Manolescu, Konstantinos Karanasos, Vasilis Vassalos, Spyros Zoupanos
2011 2011 IEEE 27th International Conference on Data Engineering  
The XQuery dialect we use to express views and queries corresponds to tree patterns (returning data from several nodes, at different granularities, ranging from node identifiers to full XML subtrees) with  ...  We provide correct and complete algorithms for finding minimal rewritings, in which no view is redundant.  ...  This extends the problem of XPath intersection [4] to more complex patterns (and corresponding XQuery queries).  ... 
doi:10.1109/icde.2011.5767915 dblp:conf/icde/ManolescuKVZ11 fatcat:q6d5yaru4fhy5afdas6kvrxime


Guilherme Damasio, Spencer Bryson, Vincent Corvinelli, Parke Godfrey, Piotr Mierzejewski, Jaroslaw Szlichta, Calisto Zuzarte
2019 Proceedings of the VLDB Endowment  
The tool automatically learns recurring problem patterns in query plans over workloads in an offline learning phase to build a knowledge base of plan rewrite remedies.  ...  GALO's knowledge base is built on RDF and SPARQL, which is well-suited for manipulating and querying over SQL query plans, which are graphs themselves.  ...  Large SQL queries are decomposed into smaller parts corresponding to sub-queries to find problematic patterns that can be applied over the query workloads for re-optimization.  ... 
doi:10.14778/3352063.3352064 fatcat:kflxftkslzhvtifq24l7t4eawi

Guided Automated Learning for query workload re-Optimization [article]

Guilherme Damasio, Vincent Corvinelli, Parke Godfrey, Piotr Mierzejewski, Alexandar Mihaylov, Jaroslaw Szlichta, Calisto Zuzarte
2019 arXiv   pre-print
The tool automatically learns recurring problem patterns in query plans over workloads in an offline learning phase, to build a knowledge base of plan-rewrite remedies.  ...  Query optimization is a hallmark of database systems enabling complex SQL queries of today's applications to be run efficiently.  ...  IBM experts report that even more complex patterns / rewrites (b) Plan by GALO.  ... 
arXiv:1901.02049v3 fatcat:qavhynsrnbasdn5mh4ttpwyine

Guided automated learning for query workload re-optimization

Guilherme Damasio, Vincent Corvinelli, Parke Godfrey, Piotr Mierzejewski, Alex Mihaylov, Jaroslaw Szlichta, Calisto Zuzarte
2019 Proceedings of the VLDB Endowment  
GALO acts as a third-tier of reoptimization, after query rewrite and cost-based optimization, as a query plan rewrite.  ...  The tool automatically learns recurring problem patterns in query plans over workloads in an offline learning phase, to build a knowledge base of plan-rewrite remedies.  ...  IBM experts report that even more complex patterns / rewrites exist that are more daunting, which can take days to be found and resolved.  ... 
doi:10.14778/3352063.3352120 fatcat:ru5iawhcrfcvle4wcvescr2lxu

PIWD: A Plugin-based Framework for Well-Designed SPARQL [article]

Xiaowang Zhang and Zhenyu Song and Zhiyong Feng and Xin Wang
2016 arXiv   pre-print
,DBpedia query log), queries built on well-designed patterns containing only AND and OPT operators (for short, WDAO-patterns) account for a large proportion among all SPARQL queries.  ...  In this paper, we present a plugin-based framework for all SELECT queries built on WDAO-patterns, named PIWD.  ...  For instance, we observe Q 2 , which corresponds to the most complex pattern in our four experimental SPARQL patterns.  ... 
arXiv:1607.07967v2 fatcat:e3dstsf6vrewbm5zkuk5lpr7vu

Rewriting nested XML queries using nested views

Nicola Onose, Alin Deutsch, Yannis Papakonstantinou, Emiran Curtmola
2006 Proceedings of the 2006 ACM SIGMOD international conference on Management of data - SIGMOD '06  
These features create key challenges that lead to fundamental extension of prior work on the problems of rewriting conjunctive and tree pattern queries.  ...  We present and analyze an algorithm for equivalent rewriting of XQueries using XQuery views which is sound and complete for a large class of XQueries featuring nesting and join equalities by value and  ...  Moreover, the test for this containment flavor has inherently higher complexity (Π p 2 -complete if applied to NEXT patterns) than for the binding stage containment we use (NP-complete in the pattern width  ... 
doi:10.1145/1142473.1142524 dblp:conf/sigmod/OnoseDPC06 fatcat:x5wlnfetjras3b74cqm5lshqaq

LotusX: A Position-Aware XML Graphical Search System with Auto-Completion

Chunbin Lin, Jiaheng Lu, Tok Wang Ling, Bogdan Cautis
2012 2012 IEEE 28th International Conference on Data Engineering  
The existing query languages for XML (e.g., XQuery) require professional programming skills to be formulated, however, learning such complex query languages is a tedious and a time consuming process that  ...  Furthermore, a new ranking strategy and a query rewriting solution are implemented to rank the results and automatically rewrite queries, respectively.  ...  Forth, twig pattern needs to be extended to support complex queries.  ... 
doi:10.1109/icde.2012.123 dblp:conf/icde/LinLLC12 fatcat:afmpmkh6efgcndt5mjdse7dc5m

Integrating Heterogeneous Data Source Using Ontology

Jinpeng Wang, Jianjiang Lu, Yafei Zhang, Zhuang Miao, Bo Zhou
2009 Journal of Software  
This prob- of query rewriting on graph pattern. In Section VI, we lem is known in the literature as query rewriting and give our algorithm to execute the query rewriting.  ...  Combining triple patterns gives a basic P, its source description DP is a tuple (QP, µ), where QP is graph pattern, more complex graph patterns can be a SPARQL query and µ is a mapping from variables ap  ... 
doi:10.4304/jsw.4.8.843-850 fatcat:urepz7hsqjf6hbbrwihjqc55ae


1996 International Journal of Cooperative Information Systems  
We present a reformulation algorithm which exploits semantic knowledge, represented as integrity assertions and mapping rules, for semantic rewriting based on pattern-matching.  ...  It is general enough to re-use the results of previously computed queries in the MDBMS.  ...  A key aspect of semantic rewriting is the pattern matching algorithm for OQL expressions.  ... 
doi:10.1142/s0218843096000166 fatcat:gyh7todizrcghcyehlxaahvh5y

Rules for query rewrite in native XML databases

Andreas M. Weiner, Christian Mathis, Theo Härder
2008 Proceedings of the 2008 EDBT workshop on Database technologies for handling XML information on the web - DataX '08  
For twig queries, we define a set of rewrite rules which initiate query graph transformations towards improved processability, e. g., to fuse adjacent binary join operators to a complex join operator.  ...  To enhance the evaluation flexibility of twig queries, we come up with further rewrite rules to prepare query graphs-even before query transformation-for making the most of existing joins and indexes.  ...  Acknowledgments We thank Sebastian Bächle and the anonymous reviewers for their valuable comments on this paper.  ... 
doi:10.1145/1416691.1416697 fatcat:hebzojaamnfmjl667dlupekscy

On rewriting XPath queries using views

Foto Afrati, Rada Chirkova, Manolis Gergatsoulis, Benny Kimelfeld, Vassia Pavlaki, Yehoshua Sagiv
2009 Proceedings of the 12th International Conference on Extending Database Technology Advances in Database Technology - EDBT '09  
In particular, under these conditions, determining the existence of a rewriting is coNP-complete. The proofs utilize various novel techniques for reasoning about XPath patterns.  ...  The problem of rewriting a query using a materialized view is studied for a well known fragment of XPath that includes the following three constructs: wildcards, descendant edges and branches.  ...  Acknowledgments We thank the anonymous referees for valuable comments.  ... 
doi:10.1145/1516360.1516381 dblp:conf/edbt/AfratiCGKPS09 fatcat:ggftafyohbhkhnmoem3hpl4eq4

Is Your Database System a Semantic Web Reasoner?

Markus Krötzsch, Sebastian Rudolph
2015 Künstliche Intelligenz  
In ontology-based query answering (OBQA), application knowledge is expressed in ontologies and used for providing better query answers.  ...  For lightweight ontology languages, this is possible using the popular Semantic Web query language SPARQL 1.1, other cases require more powerful query languages like Datalog, which is also seeing a renaissance  ...  We thank the anonymous reviewers for their comments, which helped to improve the paper.  ... 
doi:10.1007/s13218-015-0412-x fatcat:6detp2sw6vejzgtoilretvowxe

Towards Reconciling SPARQL and Certain Answers

Shqiponja Ahmetaj, Wolfgang Fischl, Reinhard Pichler, Mantas Šimkus, Sebastian Skritek
2015 Proceedings of the 24th International Conference on World Wide Web - WWW '15  
Moreover, we show that the complexity of the most fundamental query analysis tasks (such as query containment and equivalence testing) is not negatively affected by the presence of OWL 2 QL entailment  ...  For OWL 2 QL entailment, we present algorithms for the evaluation of an interesting fragment of SPARQL (the so-called well-designed SPARQL).  ...  We derive new queries by rewriting each node of the pattern tree corresponding to the above query separately. 1. We start with the first BGP (?x, teaches, ?y): We use t = (?x, teaches, ?y).  ... 
doi:10.1145/2736277.2741636 dblp:conf/www/AhmetajFPSS15 fatcat:3f2254oh7jhqdf7lptvsjefyae
« Previous Showing results 1 — 15 out of 19,259 results