Teaching an RDBMS about ontological constraints

@article{Bursztyn2016TeachingAR,
  title={Teaching an RDBMS about ontological constraints},
  author={Damian Bursztyn and François Goasdou{\'e} and Ioana Manolescu},
  journal={Proc. VLDB Endow.},
  year={2016},
  volume={9},
  pages={1161-1172}
}
In the presence of an ontology, query answers must reflect not only data explicitly present in the database, but also implicit data, which holds due to the ontology, even though it is not present in the database. A large and useful set of ontology languages enjoys FOL reducibility of query answering: answering a query can be reduced to evaluating a certain first-order logic (FOL) formula (obtained from the query and ontology) against only the explicit facts. We present a novel query… 

Figures and Tables from this paper

Optimizing FOL Reducible Query Answering: Understanding Performance Challenges
TLDR
This demonstration showcases to the attendees, and analyzes, the performance of several reformulation-based query answering techniques, including one recently described in [5], applied to the lightweight description logic DL-LiteR underpinning the W3C's OWL2 QL profile.
Rewriting-Based Query Answering for Semantic Data Integration Systems
TLDR
A new approach to query answering is introduced, based on a reduction to view-based query answering, which avoids both materialization in the data and query reformulation.
Cost-Driven Ontology-Based Data Access (Extended Version)
TLDR
It is shown that translating to UCQs is not always the best choice, and that, under certain conditions on the interplay between the ontology, the map- pings, and the statistics of the data, alternative translations can be evaluated much more efficiently.
Inconsistency Handling in Ontology-Mediated Query Answering
TLDR
This thesis aims to develop methods for dealing with inconsistent description logic knowledge bases using three natural semantics (AR, IAR, and brave) previously proposed in the literature and that rely on the notion of a repair, which is an inclusion-maximal subset of the data consistent with the ontology.
The Complexity of Ontology-Based Data Access with OWL 2 QL and Bounded Treewidth Queries
TLDR
It is shown that OMQs with bounded depth ontologies have nonrecursive datalog (NDL) rewritings that can be constructed and evaluated in LOGCFL for combined complexity, and even in NL if their CQs are tree-shaped with a bounded number of leaves.
In-memory parallelization of join queries over large ontological hierarchies
TLDR
PARJ is presented, an in-memory RDF store which takes into consideration ontological hierarchies during join processing with very low performance overhead, avoiding expensive preprocessing and materialization of implications, and is also amenable to straightforward parallelization.
Revisiting RDF storage layouts for efficient query answering
TLDR
This work considers answering Basic Graph Pattern Queries (BGPQs), and in particular those with variables in class and property positions, in the presence of RDFS ontologies, both through data saturation and query reformulation and introduces summary-based pruning, a novel technique based on existing RDF quotient summaries, which improves query answering performance.
Ontology-mediated query answering: performance challenges and advances
TLDR
A decade of OMQA optimization is showcased to understand “Where do the authors stand now and how did they get there?” and a promising new OMZA optimization that brings further significant performance improvement is highlighted to discuss “What’s next?’.
...
...

References

SHOWING 1-10 OF 41 REFERENCES
Efficient query answering in the presence of DL-LiteR constraints
TLDR
A novel query optimization framework for ontology-based data access settings enjoying FOL reducibility is presented, based on searching within a set of alternative equivalent FOL queries, i.e., FOL reformulations, one with minimal evaluation cost when evaluated through a relational database system.
Ontology-Based Query Answering with Existential Rules
TLDR
This talk will provide an introduction to an emerging logical framework based on existential rules, also known as Datalog+/-, then present the main decidability and complexity results as well as algorithmic techniques, and discuss some challenging research issues.
Query Rewriting and Optimization for Ontological Databases
TLDR
This article shows how a conjunctive query against a knowledge base, expressed using linear and sticky existential rules, that is, members of the recently introduced Datalog± family of ontology languages, can be compiled into a union of conj unctive queries (UCQ) against the underlying database.
Optimizing query answering under ontological constraints
TLDR
This paper presents a new algorithm that computes the perfect rewriting of a conjunctive query w.r.t. a linear Datalog± ontology, and provides an experimental comparison of the algorithm with existing rewriting techniques.
Improving Query Answering over DL-Lite Ontologies
TLDR
Presto is presented, a new query answering technique for DL-Lite ontologies, and an experimental comparison of Presto with the main previous approaches to query answering in DL- Lite shows that it is significantly more efficient.
A general datalog-based framework for tractable query answering over ontologies
TLDR
It is shown in particular that Datalog+/- generalizes the DL-Lite family of tractable description logics, which are the most common tractable ontology languages in the context of the Semantic Web and databases.
Compact Rewriting for Existential Rules
TLDR
This paper considers ontologies described by existential rules (also known as Datalog+/-), a framework that generalizes lightweight description logics, and proposes semi-conjunctive queries (SCQ), which are a restricted form of positive existential formulas, and USCQ, which are union of SCQ (USCQ).
Optimizing Reformulation-based Query Answering in RDF
TLDR
This paper considers optimizing reformulation-based query answering in the setting of ontology-based data access, where SPARQL conjunctive queries are posed against RDF facts on which constraints expressed by an RDF Schema hold.
Compact Rewritings for Existential Rules
TLDR
This paper considers ontologies described by existential rules (also known as Datalog+/-), a framework that generalizes lightweight description logics, and proposes semi-conjunctive queries (SCQ), which are a restricted form of positive existential formulas, and USCQ, which are union of SCQ (USCQ).
Datalog±: a unified approach to ontologies and integrity constraints
TLDR
This survey mainly summarizes two recent papers on Datalog±, a new framework for representing ontological axioms in form of integrity constraints, and for query answering under such constraints, that can be successfully employed in different contexts such as data integration and exchange.
...
...