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Containment of Simple Regular Path Queries [article]

Diego Figueira and Adwait Godbole and S. Krishna and Wim Martens and Matthias Niewerth and Tina Trautner
2020 arXiv   pre-print
We study here the containment problem for Conjunctive Regular Path Queries (CRPQs), a navigational query language extensively used in ontology and graph database querying.  ...  We obtain a detailed overview of the complexity of the containment problem, depending on the features used in the regular expressions of the queries, with completeness results for np, pitwo, pspace or  ...  Although much of the work on querying knowledge bases is focused on conjunctive queries, there is often the need to use a simple form of recursion, such as the one provided by regular path queries (RPQ  ... 
arXiv:2003.04411v1 fatcat:chvvu3lmxjdm3ndsavyxca5mw4

Query containment for conjunctive queries with regular expressions

Daniela Florescu, Alon Levy, Dan Suciu
1998 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems - PODS '98  
For a restricted class of conjunctive queries with regular path exrepssions we s h o w that containment and equivalence are NP-complete.  ...  All query languages proposed for semistructured data share as common characteristic the ability to traverse arbitrary long path in the data in the form of regular path expressions.  ...  A simple StruQL 0 query is a StruQL 0 query in which all regular expressions are simple.  ... 
doi:10.1145/275487.275503 dblp:conf/pods/FlorescuLS98 fatcat:kehgwth2efhlhpj4noi5poanhq

Weighted path queries on semistructured databases

Sergio Flesca, Filippo Furfaro, Sergio Greco
2006 Information and Computation  
Weighted path queries are based on the notion of weighted regular expression, i.e., a regular expression whose symbols are associated to a weight.  ...  In this paper we introduce weighted path queries, an extension of path queries enabling several classes of optimization problems (such as the computation of shortest paths) to be easily expressed.  ...  The semantics of weighted path queries and weighted simple path queries is as follows.  ... 
doi:10.1016/j.ic.2005.12.002 fatcat:kjz56kwfyfcojj7zwdn2niblhy

Finding Regular Simple Paths in Graph Databases

Alberto O. Mendelzon, Peter T. Wood
1995 SIAM journal on computing (Print)  
We consider the following problem: given a labelled directed graph G and a regular expression R, find all pairs of nodes connected by a simple path such that the concatenation of the labels along the path  ...  The problem is motivated by the observation that many recursive queries can be expressed in this form, and by the implementation of a query language, G+, based on this observation.  ...  ACKNOWLEDGEMENTS This research was supported by the Natural Sciences and Engineering Research Council of Canada. We thank Mariano Consens and the anonymous reviewers for useful comments.  ... 
doi:10.1137/s009753979122370x fatcat:jqpjbabttfhwnku2mywe5r5lsm

XRel: a path-based approach to storage and retrieval of XML documents using relational databases

Masatoshi Yoshikawa, Toshiyuki Amagasa, Takeyuki Shimura, Shunsuke Uemura
2001 ACM Transactions on Internet Technology  
For processing XML queries, we present an algorithm for translating a core subset of XPath expressions into SQL queries.  ...  In this approach, an XML document is decomposed into nodes on the basis of its tree structure and stored in relational tables according to the node type, with path information from the root to each node  ...  Therefore, to process the general form of path expressions in XPathCore, we need to 'cut' a given query into fragment paths and 'splice' them into the complete form of simple absolute regular expressions  ... 
doi:10.1145/383034.383038 fatcat:7pc5vjbzpraltbnkfh56inp7ui

G-path

Yiyuan Bai, Chaokun Wang, Yuanchi Ning, Hanzhao Wu, Hao Wang
2013 Proceedings of the 22nd International Conference on World Wide Web - WWW '13 Companion  
In this paper, we present a system of path query on large graphs, known as G-Path.  ...  With the flexibility of G-Path, the application is able to handle different kinds of queries.  ...  In this paper, we bring forward the design and implementation of G-Path, a regular path query language on graphs, which supports mostly all useful regular expression operators (group operator, parallel  ... 
doi:10.1145/2487788.2487937 dblp:conf/www/BaiWNWW13 fatcat:unmiiegtpzfnndhiqrbmzzw6zq

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.  ...  For that purpose, we define a language, called PRDF (for "Path RDF") which extends RDF such that the arcs of a graph can be labeled by regular expression patterns.  ...  in paths, e.g., simple or non-simple paths, presence of a pattern in a path.  ... 
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.  ...  For that purpose, we define a language, called PRDF (for "Path RDF") which extends RDF such that the arcs of a graph can be labeled by regular expression patterns.  ...  in paths, e.g., simple or non-simple paths, presence of a pattern in a path.  ... 
doi:10.2139/ssrn.3199439 fatcat:xxqpmbiorjgi7c7duafnqamsk4

A partition index for XML and semi-structured data*1, *2

J KIM, H KIM
2004 Data & Knowledge Engineering  
The paths in a data graph are used as a basic constructor of a query. Especially, by using patterns on paths, a user can formulate more expressive queries.  ...  In this paper, we introduce a partitioning technique for all paths in a data graph and an index graph which can effectively find appropriate path partitions for a path query with patterns.  ...  One group contains simple path expressions which do not use regular expressions, and the other contains regular path expressions which use only '_Ã'.  ... 
doi:10.1016/s0169-023x(04)00082-5 fatcat:rwxgk4szizedfg6gip2k7i2vk4

A partition index for XML and semi-structured data

Jongik Kim, Hyoung-Joo Kim
2004 Data & Knowledge Engineering  
The paths in a data graph are used as a basic constructor of a query. Especially, by using patterns on paths, a user can formulate more expressive queries.  ...  In this paper, we introduce a partitioning technique for all paths in a data graph and an index graph which can effectively find appropriate path partitions for a path query with patterns.  ...  One group contains simple path expressions which do not use regular expressions, and the other contains regular path expressions which use only '_Ã'.  ... 
doi:10.1016/j.datak.2004.06.001 fatcat:dly5hbe4pzefneorvewew7dbk4

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.  ...  We formalize the W3C semantics of property paths and investigate various query evaluation problems on graphs.  ...  We thank Marcelo Arenas for sending us a draft of [5] and for his comments on a draft of this paper; Thomas Schwentick for pointing out that emptiness testing of starfree regular expressions with negation  ... 
doi:10.1145/2213556.2213573 dblp:conf/pods/LosemannM12 fatcat:jezhx4k7s5e43oeaw7etu2po5a

Anatomy of the coupling query in a web warehouse

Sourav S. Bhowmick, Wee Keong Ng, Sanjay Madria, Ee-Peng Lim
2002 Information and Software Technology  
of the topological structure of hyperlinked documents in the query results.  ...  Some of the important features of our query mechanism are ability to query metadata, content, internal and external (hyperlink) structure of Web documents based on partial knowledge, ability to express  ...  With the above two types of link components, a link path expression is simple if the path expression contains only a simple link component. Otherwise, it is a regular link path expression.  ... 
doi:10.1016/s0950-5849(02)00051-4 fatcat:i7gl32rulzephfy6metwdd3lu4

Finding Top-k Approximate Answers to Path Queries [chapter]

Carlos A. Hurtado, Alexandra Poulovassilis, Peter T. Wood
2009 Lecture Notes in Computer Science  
The query language we adopt comprises conjunctions of regular path queries, allowing path variables to appear in the bodies and the heads of rules, so that paths can be returned to the user.  ...  However, in that work we did not allow path variables within queries, and were not able to return paths as results to users' queries. Here, we consider extended regular path (ERP) queries of the form:  ...  A simple ERP query is an expression of the form: X, P, Y ← (X, (R : P ), Y ) where X and Y are constants or variables, R is a regular expression over Σ, and P is a path variable.  ... 
doi:10.1007/978-3-642-04957-6_40 fatcat:y5ujzl7uk5gwppiacohdq4rmbe

Local searching the Internet

M. Angelaccio, B. Buttarazzi
2002 IEEE Internet Computing  
Local searching tools search pages on or close to a site to answer specific queries. A Web query taxonomy based on WebSQL can help enhance local searching techniques.  ...  Bounded Local Queries You can execute bounded local queries easily in terms of regular path expressions.  ...  global queries by Q index (with keyword and regular path expression as arguments) and the class of local queries by Q neigh (with starting URL i, keyword k, and regular path expression R as arguments).  ... 
doi:10.1109/4236.978366 fatcat:au3oakuw4zdbdfkwqwnl774eti

Index Structures for Path Expressions [chapter]

Tova Milo, Dan Suciu
1999 Lecture Notes in Computer Science  
Acknowledgment: We thank Micky Frankel for the implementation of the 1-, 2and T-indexes.  ...  In the case of semistructured data, queries are even more complex, because they may contain regular path expressions [1, 7, 8, 16] .  ...  Define a regular path expression to be simple if it consists of a concatenation of (1) constants from D, (2) , and (3) * . For example * .A. * .B. . .C is a simple regular path expression.  ... 
doi:10.1007/3-540-49257-7_18 fatcat:ceordeq2ezcmlkpfc2cvkfzrle
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