LINKS - 2018

Section: New Results

Querying Heterogeneous Linked Data

Data Integration

The PhD project of Lozano on relational to RDF data integration is progressing under the direction of Boneva, and Staworko. At AMW [9] they studied the relational to RDF data exchange problem. They focus in particular on a preliminary analysis of the consistency problem for relational to RDF data exchange with target ShEx schema.

Schema Validation

Shape Expression Language 2.0 (ShEx) is a language to describe the vocabulary and the structure of an RDF graph. It is base on the notion of shapes, a typing system supporting algebraic operations, recursive references to other shapes or Boolean combination.

In their PODS paper [7], Staworko studied the containment problem for ShEx (in cooperation with Wieczorek from Wrazlaw). Containement is a classical subject for schema-related issue in database theory. The authors proved that it is decidable for ShEx-schema, but with a untractable complexity (co-NEXP -hard). They also carefuly craft restriction of ShEx schema to design tractable-but-still-signifiant fragments.