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Evaluating SPARQL-to-SQL translation in ontop

by Mariano Rodriguez-muro, Martin Rezk, Josef Hardi, Mindaugas Slusnys, Timea Bagosi, Diego Calvanese
"... Abstract. In this paper we evaluate the performance of the SQL queries generated by ontop, a system that uses a formal approach to translate and optimize SPARQL queries and R2RML mappings. We show that the performance of ontop’s SQL queries is superior to that of the performance of well known system ..."
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Abstract. In this paper we evaluate the performance of the SQL queries generated by ontop, a system that uses a formal approach to translate and optimize SPARQL queries and R2RML mappings. We show that the performance of ontop’s SQL queries is superior to that of the performance of well known

OBDA with the Ontop Framework

by Diego Calvanese, Benjamin Cogrel, Elem Guzel Kalayci, Sarah Komla Ebri, Roman Kontchakov, Davide Lanti, Martin Rezk, Mariano Rodriguez-muro, Guohui Xiao
"... Abstract. Ontology-based data access (OBDA) has become a popular paradigm for accessing data stored in legacy sources using Semantic Web technologies. In the OBDA setting, users access the data through a con-ceptual layer, which provides a convenient query vocabulary abstracting from specific aspect ..."
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sources and construct the answers expected by the user. Different approaches for query processing in OBDA have been proposed. We focus here on the virtual approach, which avoids materializing triples retrieved through mappings and an-swers the SPARQL queries by translating them into SQL queries over

Evaluation of SPARQL Property Paths via Recursive SQL

by Nikolay Yakovets, Parke Godfrey, Jarek Gryz
"... Abstract. Property paths, a part of the proposed SPARQL 1.1 standard, allow for non-trivial navigation in RDF graphs. We investigate the evaluation of SPARQL queries with property paths in a relational RDF store. We propose a translation of SPARQL property paths into recursive SQL and discuss possib ..."
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Abstract. Property paths, a part of the proposed SPARQL 1.1 standard, allow for non-trivial navigation in RDF graphs. We investigate the evaluation of SPARQL queries with property paths in a relational RDF store. We propose a translation of SPARQL property paths into recursive SQL and discuss

XML-to-SQL Query Translation

by Rajasekar Krishnamurthy , 2004
"... Developing techniques for managing and querying the growing body of XML data is becomingly increasingly important. A popular approach to evaluating XML queries is to translate them to relational queries and then to use a relational database system to evaluate the result. The XML and relational data ..."
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Developing techniques for managing and querying the growing body of XML data is becomingly increasingly important. A popular approach to evaluating XML queries is to translate them to relational queries and then to use a relational database system to evaluate the result. The XML and relational data

D.: Rules and ontology based data access

by Guohui Xiao, Martin Rezk, Diego Calvanese - In: Proc. of the 8th Int. Conf. on Web Reasoning and Rule Systems (RR). Lecture Notes in Computer Science , 2014
"... Abstract. In OBDA an ontology defines a high level global vocabulary for user queries, and such vocabulary is mapped to (typically relational) databases. Ex-tending this paradigm with rules, e.g., expressed in SWRL or RIF, boosts the ex-pressivity of the model and the reasoning ability to take into ..."
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into account features such as recursion and n-ary predicates. We consider evaluation of SPARQL queries un-der rules with linear recursion, which in principle is carried out by a 2-phase trans-lation to SQL: (1) The SPARQL query, together with the RIF/SWRL rules, and the mappings is translated to a Datalog

Ultrawrap: SPARQL Execution on Relational Data

by Juan F. Sequeda, Daniel P. Miranker
"... Abstract: The Semantic Web’s promise to achieve web-wide data integration requires the inclusion of legacy relational data as RDF, which, in turn, requires the execution of SPARQL queries on the legacy relational database. In this paper we explore a hypothesis: existing commercial relational databas ..."
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translation of SPARQL queries to SQL queries on those views. Thus, in the course executing a SPARQL query, the SQL optimizer both instantiates a mapping of relational data to RDF and optimizes its execution. Other approaches typically implement aspects of query optimization and execution outside the SQL

2014c. Predictive Translation Memory: A mixed-initiative system for human language translation

by Spence Green , Jason Chuang , Jeffrey Heer , Christopher D Manning - In UIST
"... ABSTRACT The standard approach to computer-aided language translation is post-editing: a machine generates a single translation that a human translator corrects. Recent studies have shown this simple technique to be surprisingly effective, yet it underutilizes the complementary strengths of precisi ..."
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Chinese-to-English system in which human translators annotate the input extensively (phrase boundaries, word senses, etc.). Unpublished results showed greatly reduced post-editing effort to achieve human quality To our knowledge, TransType was the first interactive system TransType2 [16] added a

EMBEDDING XPATH QUERIES INTO SPARQL QUERIES

by Matthias Droop, Markus Flarer, Volker Linnemann, Florian Santner, Michael Schier, Felix Schöpf, Hannes Staffler, Stefan Zugal
"... While XPath is an established query language developed by the W3C for XML, SPARQL is a new query language developed by the W3C for RDF data. Comparisons between the data models of XML and RDF and between the query languages XPath and SPARQL are missing. Since XML and XPath are earlier recommendation ..."
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recommendations of the W3C than RDF and SPARQL, currently more XML data and XPath queries are used in applications. However, recently available SPARQL query evaluators do not deal with XML data and XPath queries. We have developed a prototype for translating XML data into RDF data and embedding XPath queries

From Complete to Incomplete Information and Back

by Lyublena Antova, Christoph Koch, Dan Olteanu - In Proc. SIGMOD
"... Incomplete information arises naturally in numerous data management applications. Recently, several researchers have studied query processing in the context of incomplete information. Most work has combined the syntax of a traditional query language like relational algebra with a nonstandard semanti ..."
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semantics such as certain or ranked possible answers. There are now also languages with special features to deal with uncertainty. However, to the standards of the data management community, to date no language proposal has been made that can be considered a natural analog to SQL or relational algebra

A Scalable Benchmark for OBDA Systems: Preliminary Report?

by Diego Calvanese, Davide Lanti, Martin Rezk, Mindaugas Slusnys, Guohui Xiao
"... Abstract. In ontology-based data access (OBDA), the aim is to provide a high-level conceptual view over potentially very large (relational) data sources by means of a mediating ontology. The ontology is connected to the data sources through a declarative specification given in terms of mappings that ..."
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that relate each (class and prop-erty) symbol in the ontology to an (SQL) view over the data. Although prototype OBDA systems providing the ability to answer SPARQL queries over the ontology are available, a significant challenge remains: performance. To properly evaluate OBDA systems, benchmarks tailored
Results 1 - 10 of 38