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Containment of Simple Regular Path Queries
[article]
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
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
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
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
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
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)
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
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
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
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
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
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]
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
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]
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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