9.5: Exercises
- Page ID
- 6454
Exercise \(\PageIndex{1}\)
Describe in your own words what an OBDA system is. Try to keep it short, such that you can explain it in less than 30 seconds.
Exercise \(\PageIndex{2}\)
What are the principal components of the OBDA system described in some detail in this chapter?
Exercise \(\PageIndex{3}\)
How is querying in the OBDA setting different compared to plain relational database?
Exercise \(\PageIndex{4}\)
Inspect an ontology used for OBDA; e.g.,: the one of the EPnet5 or one from the Ontop examples6. Consider again Section 1.2: What is an Ontology? "The Definition Game" regarding the differences between ontologies and conceptual models and Chapter 6 on foundational ontologies. Why does the ‘ontology’ in an OBDA system look more like an OWLized conceptual data model?
- Answer
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Two of the reasons:
- the ontology is specific to the application, hater than being application-independent. If it wouldn’t be, then there will be mismatches (either too much/irrelevant content in the ontology, or data that should be queried but can’t if there’s no corresponding knowledge in the ontology)
- the ontology contains implementation decisions, such as data properties, which will hamper any reuse, be that for another application or as a module of another ontology.
Exercise \(\PageIndex{5}\)
You will set up an OBDA system. Consult the wiki at https://github.com/ontop/ontop/wiki for tutorials and sample data, and the software at https://github.com/ontop/ontop.
Footnotes
5http://romanopendata.eu/sparql/doc/index.html
6e.g., movies: https://github.com/ontop/ontop/wiki/..._MovieOntology