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Query Rewriting and Optimisation with Database Dependencies in Ontop

Mariano Rodriguez-Muro, Roman Kontchakov, Michael Zakharyaschev
2013 International Workshop on Description Logics  
We discuss the theoretical foundations of Ontop, including the tree-witness query rewriting, T -mappings and optimisations based on database integrity constraints and SQL features.  ...  We present technologies that underpin the OBDA system Ontop and take full advantage of storing data in relational databases.  ...  We thank the Ontop team-Timea Bagosi, Josef Hardi and Mindaugas Slusnys-at the Free University of Bozen-Bolzano for their help in developing the system and running experiments.  ... 
dblp:conf/dlog/Rodriguez-MuroKZ13 fatcat:ke7qttgevvbtxogyzo3k3sealy

Ontology-Based Data Access: Ontop of Databases [chapter]

Mariano Rodríguez-Muro, Roman Kontchakov, Michael Zakharyaschev
2013 Lecture Notes in Computer Science  
We discuss the theoretical foundations of Ontop: the tree-witness query rewriting, T -mappings and optimisations based on database integrity constraints and SQL features.  ...  We analyse the performance of Ontop in a series of experiments and demonstrate that, for standard ontologies, queries and data stored in relational databases, Ontop is fast, efficient and produces SQL  ...  Xiao for providing queries and the Ontop development team (J. Hardi, T. Bagosi, M. Slusnys) for the help with the experiments.  ... 
doi:10.1007/978-3-642-41335-3_35 fatcat:2v63lldztfahlhryhysdcr32ui

Ontop at Work

Mariano Rodriguez-Muro, Roman Kontchakov, Michael Zakharyaschev
2013 W3C Web Ontology Language (OWL) Experiences and Directions Workshop (OWLED)  
We demonstrate that, for standard ontologies, queries and data stored in relational databases, Ontop is fast, efficient and produces SQL rewritings of high quality.  ...  We describe the architecture of the OBDA system Ontop and analyse its performance in a series of experiments.  ...  Cicala and A. Taccella for their help on the ILog experiments and the Ontop development team (J. Hardi, T. Bagosi and M. Slusnys) for their help with the experiments.  ... 
dblp:conf/owled/Rodriguez-MuroKZ13 fatcat:fjut7v4e3zbufhuidow2etmpoe

OBDA with Ontop

Mariano Rodriguez-Muro, Roman Kontchakov, Michael Zakharyaschev
2013 International Workshop on OWL Reasoner Evaluation  
Our experiments show that (i) the Ontop tree-witness query rewriter is fast and outperforms the competitors, and (ii) query evaluation in Ontop using the semantic index is as efficient as in materialisation-based  ...  We evaluate the performance of the OBDA system Ontop and compare it with other systems.  ...  We thank Giorgio Orsi for providing Nyaya, Guohui Xiao for providing queries and the Ontop development team (Josef Hardi, Timea Bagosi and Mindaugas Slusnys) for their help with the experiments.  ... 
dblp:conf/ore/Rodriguez-MuroKZ13 fatcat:w4mwmvrezfewhditbk4wvepv6m

Rules and Ontology Based Data Access [chapter]

Guohui Xiao, Martin Rezk, Mariano Rodríguez-Muro, Diego Calvanese
2014 Lecture Notes in Computer Science  
In OBDA an ontology defines a high level global vocabulary for user queries, and such vocabulary is mapped to (typically relational) databases.  ...  We implement and evaluate the techniques presented here in the Ontop system.  ...  We thank Héctor Pérez-Urbina for his support in evaluating Stardog.  ... 
doi:10.1007/978-3-319-11113-1_11 fatcat:uqm6evalvjfy3ffrn4qpfxem54

Answering SPARQL Queries over Databases under OWL 2 QL Entailment Regime [chapter]

Roman Kontchakov, Martin Rezk, Mariano Rodríguez-Muro, Guohui Xiao, Michael Zakharyaschev
2014 Lecture Notes in Computer Science  
hierarchies, and T -mapping optimisations using SQL expressivity and database integrity constraints-the system produces scalable SQL queries.  ...  On the practical side, we present initial experimental results demonstrating that by applying the Ontop technologies-the tree-witness query rewriting, T -mappings compiling R2RML mappings with ontology  ...  Komla-Ebri for help with the experiments, and I. Kollia and B. Glimm for discussions.  ... 
doi:10.1007/978-3-319-11964-9_35 fatcat:qxyznp6o3baldm7flrw4gjouki

A semantic approach to polystores

E. Kharlamov, T. Mailis, K. Bereta, D. Bilidas, S. Brandt, E. Jimenez-Ruiz, S. Lamparter, C. Neuenstadt, O. Ozcep, A. Soylu, C. Svingos, G. Xiao (+8 others)
2016 2016 IEEE International Conference on Big Data (Big Data)  
In the database community Polystores is an emerging and promising approach for data federation that aims at designing a unified querying layer over multiple data models.  ...  In the Semantic Web community a similar in spirit approach of Ontology-Based Data Access (OBDA) has been recently proposed, attracted a lot of attention, and proved its success in several industrial scenarios  ...  The core of ONTOP is the SPARQL engine Quest, which is in charge of rewriting SPARQL queries over the virtual RDF graph into SQL queries over the relational database.  ... 
doi:10.1109/bigdata.2016.7840898 dblp:conf/bigdataconf/KharlamovMBBBJL16 fatcat:qoo6qitn4nf6jiqwltr7ehqj3a

Ontology-Based Data Access with Databases: A Short Course [chapter]

Roman Kontchakov, Mariano Rodríguez-Muro, Michael Zakharyaschev
2013 Lecture Notes in Computer Science  
An OBDA system rewrites such queries and ontologies into the vocabulary of the data sources and then delegates the actual query evaluation to a suitable query answering system such as a relational database  ...  We consider different types of conjunctive query rewriting and their succinctness, different architectures of OBDA systems, and give an overview of the OBDA system Ontop.  ...  An OBDA system such as Ontop available at ontop.inf.unibz.it will automatically rewrite your query into the language of IMDb, optimise the rewriting and use a conventional relational database management  ... 
doi:10.1007/978-3-642-39784-4_5 fatcat:kn5f4iuvtrepdmgvk5bp7psn2i

An Introduction to Description Logics and Query Rewriting [chapter]

Roman Kontchakov, Michael Zakharyaschev
2014 Lecture Notes in Computer Science  
We also discuss the semantical foundations for first-order and datalog rewritings of conjunctive queries over knowledge bases given in the OWL 2 profiles, and outline the architecture of the ontology-based  ...  data access system Ontop.  ...  Unfolding with Semantic Query Optimisation (SQO) Ontop applies the Semantic Query Optimisation (Chakravarthy et al., 1986) to rules obtained at the intermediate steps of unfolding.  ... 
doi:10.1007/978-3-319-10587-1_5 fatcat:mgqujsvxl5erlkoftaihiuqgoa

ForBackBench: A Benchmark for Chasing vs. Query-Rewriting

Afnan G. Alhazmi, Tom Blount, George Konstantinidis
2022 Proceedings of the VLDB Endowment  
execution of a DE/OBDA scenario across areas and among dierent chase and query-rewriting systems.  ...  In OBDA, backward-chaining algorithms rewrite the query over the source schema, taking the ontology into account, in order to execute the rewriting directly on the sources.  ...  Alhazmi was parially supported by the Fundamental Research Funds for Saudi Culture Mission in UK. We thank James Errington and Nathan Bharkhda for helping with early features of the implementation.  ... 
dblp:journals/pvldb/AlhazmiBK22 fatcat:hx3were5ezcoxjc3l4dgbbbchy

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.  ...  Databases and semantic technologies are an excellent match in scenarios requiring the management of heterogeneous or incomplete data.  ...  Acknowledgements This work has been supported by the DFG in project DIAMOND (Emmy Noether Grant KR 4381/1-1) and in project HAEC (DFG SFB 912), which is part of the cfAED Cluster of Excellence.  ... 
doi:10.1007/s13218-015-0412-x fatcat:6detp2sw6vejzgtoilretvowxe

UNiCS: The Open Data Platform for Research and Innovation

Xavi Gimenez, Alessandro Mosca, Fernando Roda, Bernardo Rondelli, Guillem Rull
2018 International Conference on Semantic Systems  
In UNiCS, each query gets transformed in a set of optimised queries to different data sources.  ...  The UNiCS platform follows the Ontology-Based Data Access (OBDA) approach, which eases the access to a vast amount of heterogeneous data and offers the final users the possibility to formulate queries  ...  relational databases as Virtual RDF Graphs via query-rewriting [2] .  ... 
dblp:conf/i-semantics/GimenezMRRR18 fatcat:732wj6lyrne4ribf626rua5exy

Ontology Based Data Access in Statoil

Evgeny Kharlamov, Dimitris Bilidas, Dag Hovland, Ernesto Jimenez-Ruiz, Davide Lanti, Hallstein Lie, Martin Rezk, Martin G. Skjjveland, Ahmet Soylu, Guohui Xiao, Dimitriy Zheleznyakov, Martin Giese (+4 others)
2017 Social Science Research Network  
In particular, we have developed a deployment module to create ontologies and mappings from relational databases in a semi-automatic fashion; a query processing module to perform and optimise the process  ...  Our modules have been integrated in one OBDA system, deployed at Statoil, integrated with Statoil's infrastructure, and evaluated with Statoil's engineers and data.  ...  This work was partially funded by the EU project Optique (FP7-ICT-318338), the EPSRC projects MaSI 3 , DBOnto, ED 3 , the BIGMED project (IKT 259055), and the SIRIUS Centre for Scalable Data Access (Research  ... 
doi:10.2139/ssrn.3199136 fatcat:l23bxm5dgrcolfr4p43cs6efre

Ontology Based Data Access in Statoil

Evgeny Kharlamov, Dag Hovland, Martin G. Skjæveland, Dimitris Bilidas, Ernesto Jiménez-Ruiz, Guohui Xiao, Ahmet Soylu, Davide Lanti, Martin Rezk, Dmitriy Zheleznyakov, Martin Giese, Hallstein Lie (+4 others)
2017 Journal of Web Semantics  
In particular, we have developed a deployment module to create ontologies and mappings from relational databases in a semi-automatic fashion; a query processing module to perform and optimise the process  ...  Our modules have been integrated in one OBDA system, deployed at Statoil, integrated with Statoil's infrastructure, and evaluated with Statoil's engineers and data.  ...  This work was partially funded by the EU project Optique (FP7-ICT-318338), the EPSRC projects MaSI 3 , DBOnto, ED 3 , the BIGMED project (IKT 259055), and the SIRIUS Centre for Scalable Data Access (Research  ... 
doi:10.1016/j.websem.2017.05.005 fatcat:ghpdmsaoizc6bgly4cuyxljvq4

SPARQL-to-SQL on Internet of Things Databases and Streams [chapter]

Eugene Siow, Thanassis Tiropanis, Wendy Hall
2016 Lecture Notes in Computer Science  
We show that storage efficiency, with succinct row storage, and query performance can be improved from 2 times to 3 orders of magnitude.  ...  To realise a semantic Web of Things, the challenge of achieving efficient Resource Description Format (RDF) storage and SPARQL query performance on Internet of Things (IoT) devices with limited resources  ...  As timestamps are not unique in LSD (observed from data), they are not suited as a primary key, hence cannot be used to chase equality generating dependencies in the semantic query optimisation ontop does  ... 
doi:10.1007/978-3-319-46523-4_31 fatcat:i5hey7j7hjabvf5yvx6hulxmi4
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