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The complexity of evaluating path expressions in SPARQL

Katja Losemann, Wim Martens
2012 Proceedings of the 31st symposium on Principles of Database Systems - PODS '12  
Property paths allow SPARQL queries to evaluate regular expressions over graph data. However, they differ from standard regular expressions in several notable aspects.  ...  The World Wide Web Consortium (W3C) recently introduced property paths in SPARQL 1.1, a query language for RDF data.  ...  is non-elementary (i.e, Theorem 3.5); and Pekka Kilpeläinen for giving us the 1979 reference for dynamic programming for evaluating regular expressions on strings.  ... 
doi:10.1145/2213556.2213573 dblp:conf/pods/LosemannM12 fatcat:jezhx4k7s5e43oeaw7etu2po5a

Federation and Navigation in SPARQL 1.1 [chapter]

Marcelo Arenas, Jorge Pérez
2012 Lecture Notes in Computer Science  
federated queries and the high computational complexity of the evaluation problem for queries including navigation functionalities.  ...  Since the release of its first version in 2008, the W3C group in charge of the standard has been working on extensions of the language to be included in the new version, SPARQL 1.1.  ...  The complexity of evaluating property-path SPARQL queries In this section, we show some of the results presented in [5, 19] on the complexity of evaluating property paths according to the semantics proposed  ... 
doi:10.1007/978-3-642-33158-9_3 fatcat:vtnu3llk3naf7kivy3bz3orn5y

Counting beyond a Yottabyte, or how SPARQL 1.1 property paths will prevent adoption of the standard

Marcelo Arenas, Sebastián Conca, Jorge Pérez
2012 Proceedings of the 21st international conference on World Wide Web - WWW '12  
To formally explain this fact, we conduct a theoretical study of the computational complexity of property paths evaluation.  ...  This has led the W3C to include the property path feature in the upcoming version of the standard, SPARQL 1.1.  ...  In this paper, we study the semantics of property paths and the complexity of evaluating them.  ... 
doi:10.1145/2187836.2187922 dblp:conf/www/ArenasCP12 fatcat:wpjfcgedpnfynjjvovhxljwbiy

SPARQL with Property Paths [chapter]

Egor V. Kostylev, Juan L. Reutter, Miguel Romero, Domagoj Vrgoč
2015 Lecture Notes in Computer Science  
In particular, using techniques from automata theory we show that in this case property paths do not increase the complexity of evaluation, but have a significant effect on containment and subsumption.  ...  Blending standard SPARQL and graph databases techniques we can show that adding OPT usually makes evaluation more difficult, but almost always leaves the complexity of the optimisation problems intact.  ...  Property Path Expressions We start with the definition of property path expressions, following the SPARQL 1.1 specification [10] .  ... 
doi:10.1007/978-3-319-25007-6_1 fatcat:jka4xx3b6nbo7cfugf7wzlo2dm

Context-Free Path Queries on RDF Graphs [article]

Xiaowang Zhang, Zhiyong Feng, Xin Wang, Guozheng Rao, Wenrui Wu
2016 arXiv   pre-print
Most of the navigational query languages used in the RDF community, e.g. property paths in W3C SPARQL 1.1 and nested regular expressions in nSPARQL, are based on the regular expressions.  ...  Despite the increasing expressivity, we show that cfSPARQL still enjoys a low computational complexity and can be evaluated efficiently.  ...  This work is supported by the program of the National Key Research and Development Program of China (2016YFB1000603) and the National Natural Science Foundation of China (NSFC) (61502336, 61373035).  ... 
arXiv:1506.00743v3 fatcat:jor6wnudqjcpfom5zitpcppbey

Investigating Learnability, User Performance, and Preferences of the Path Query Language SemwidgQL Compared to SPARQL [chapter]

Timo Stegemann, Jürgen Ziegler
2017 Lecture Notes in Computer Science  
To assess the applicability of SemwidgQL in real applications, we analyzed its expressiveness based on a large corpus of observed Sparql queries, showing that the language covers more than 90% of the typical  ...  In this paper, we present an empirical comparison of user performance and perceived usability for Sparql versus SemwidgQL, a path-oriented Rdf query language.  ...  Evaluation of SemwidgQL's Expressiveness To investigate how well SemwidgQL covers the range of Sparql queries used in practice we analyzed to what extent our language is able to express the queries that  ... 
doi:10.1007/978-3-319-68288-4_36 fatcat:upispofegvhgdkkfo6of7ztgem

Extending SPARQL with regular expression patterns (for querying RDF)

Faisal Alkhateeb, Jean-François Baget, Jérôme Euzenat
2009 Journal of Web Semantics  
Other languages, inspired by the work in databases, use regular expressions for searching paths in RDF graphs. Each approach can express queries that are out of reach of the other one.  ...  We show that this extension does not increase the computational complexity of SPARQL and, based on the proposed algorithm, we have implemented a correct and complete PSPARQL query engine.  ...  To evaluate the complexity of SPARQL, we consider the decision problem which consists of checking if a given assignment is an answer and is called SPARQL QUERY EVALUATION: SPARQL QUERY EVALUATION [54]  ... 
doi:10.1016/j.websem.2009.02.002 fatcat:nkjpsy2w6fafbb6ns6trgka7tq

Extending SPARQL With Regular Expression Patterns: For Querying RDF

Faisal Alkhateeb, Jean-Frannois Baget, JJrrme Euzenat
2009 Social Science Research Network  
Other languages, inspired by the work in databases, use regular expressions for searching paths in RDF graphs. Each approach can express queries that are out of reach of the other one.  ...  We show that this extension does not increase the computational complexity of SPARQL and, based on the proposed algorithm, we have implemented a correct and complete PSPARQL query engine.  ...  To evaluate the complexity of SPARQL, we consider the decision problem which consists of checking if a given assignment is an answer and is called SPARQL QUERY EVALUATION: SPARQL QUERY EVALUATION [54]  ... 
doi:10.2139/ssrn.3199439 fatcat:xxqpmbiorjgi7c7duafnqamsk4

Constrained regular expressions for answering RDF-path queries modulo RDFS

Faisal Alkhateeb, Jerome Euzenat
2014 International Journal of Web Information Systems  
Finally, we compare the expressiveness and complexity of both nSPARQL and the corresponding fragment of CPSPARQL, that we call cpSPARQL.  ...  We show that both languages have the same complexity through cpSPARQL, being a proper extension of SPARQL graph patterns, is more expressive than nSPARQL.  ...  The time complexity of PSPARQL (i.e., the complexity of evaluating a PSPARQL query against an RDF graph) is the same as that of SPARQL [2] .  ... 
doi:10.1108/ijwis-05-2013-0013 fatcat:qudamqe2wrdj7bomftwmh7z3ta

Querying Semantic Data on the Web?

Marcelo Arenas, Claudio Gutierrez, Daniel P. Miranker, Jorge Pérez, Juan F. Sequeda
2013 SIGMOD record  
Jointly with the release of RDF in 1999 as Recommendation of the W3C, the natural problem of querying RDF 1  ...  Sequeda was supported by the NSF Graduate Research Fellowship.  ...  In this section, we formalize the syntax and semantics of property paths, and study the complexity of evaluating them.  ... 
doi:10.1145/2430456.2430458 fatcat:wjzs6euyyzcm3hxt3hv5nrc2fm

Recursion in SPARQL [chapter]

Juan L. Reutter, Adrián Soto, Domagoj Vrgoč
2015 Lecture Notes in Computer Science  
In this paper we propose a general purpose recursion operator to be added to SPARQL, formalize its syntax and develop algorithms for evaluating it in practical scenarios.  ...  We also show how to implement recursion as a plug-in on top of existing systems and test its performance on several real world datasets. 9 See http://en.wikipedia.org/wiki/Six Degrees of Kevin Bacon.  ...  This work was funded by the Millennium Nucleus Center for Semantic Web Research Grant NC120004. We would like to thank Aidan Hogan, Egor Kostylev, James Cheney and the reviewers for helpful comments.  ... 
doi:10.1007/978-3-319-25007-6_2 fatcat:a464skqzm5bndcnfhqorpbqtpe

Answering SPARQL queries modulo RDF Schema with paths [article]

Faisal Alkhateeb, Jérôme Euzenat (INRIA Grenoble Rhône-Alpes / LIG Laboratoire d'Informatique de Grenoble)
2013 arXiv   pre-print
Finally, we compare the expressiveness and complexity of both nSPARQL and the corresponding fragment of CPSPARQL, that we call cpSPARQL.  ...  In particular, we show that the PSPARQL query language, a strict extension of SPARQL offering transitive closure, allows for answering SPARQL queries modulo RDFS graphs with the same complexity as SPARQL  ...  This research report sums up our knowledge about the various ways to query RDF graph modulo RDFS, providing improvements on all the existing proposals. Part of it will be published as [6].  ... 
arXiv:1311.3879v1 fatcat:hqdtvcko7ng5vhc3t4i6k5xtam

Foundations of Modern Query Languages for Graph Databases [article]

Renzo Angles, Marcelo Arenas, Pablo Barcelo, Aidan Hogan, Juan Reutter, Domagoj Vrgoc
2017 arXiv   pre-print
We conclude by discussing the importance of formalisation for graph query languages; a summary of what is known about SPARQL, Cypher and Gremlin in terms of expressivity and complexity; and an outline  ...  Thereafter we discuss navigational expressions, in which patterns can be matched recursively against the graph to navigate paths of arbitrary length; we give an overview of what kinds of expressions have  ...  paths does not affect the complexity of SPARQL query evaluation [Kostylev et al. 2015b ].  ... 
arXiv:1610.06264v3 fatcat:xd7wzmwmxvdwjau5zc5y5xguze

Towards Efficient Path Query on Social Network with Hybrid RDF Management [article]

Lei Gai, Wei Chen, Zhichao Xu, Changhe Qiu, Tengjiao Wang
2014 arXiv   pre-print
Property path query in SPARQL can express this type of operation, but its implementation suffers from performance problem considering the ever growing data size and complexity of OSN.In this paper, we  ...  In this hybrid framework, we realize an efficient in-memory algebra operator for property path query using graph traversal, and estimate the cost of this operator to cooperate with existing cost-based  ...  Query which Find pair of users in a path of friend relationship which user2 has a job and like the documents created by user1 is expressed in SPARQL as: For RDF graph in Figure 1 , this query returns  ... 
arXiv:1405.6500v2 fatcat:yfyym5stofamvgsc2d6h3757ym

A RPL through RDF: Expressive Navigation in RDF Graphs [chapter]

Harald Zauner, Benedikt Linse, Tim Furche, François Bry
2010 Lecture Notes in Computer Science  
RPL (pronounced "ripple") is the most expressive path lan-  ...  To the best of our knowledge, this demo is the first implementation of NREs (or similarly expressive RDF path languages) with this complexity.  ...  expressions and predicates with negation push RPL to the limits of RDF path languages with polynomial data complexity.  ... 
doi:10.1007/978-3-642-15918-3_25 fatcat:jregzsalazfotflguyf22qqeai
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