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Mastro in Protégé!

Protégé is the world's most popular and widely-used ontology editor. It offers a free and open-source environment for editing OWL 2 and RDF ontologies. Protégé is Java-based and is extensible through plug-ins. Now users can access all the features provided by the Mastro system, plus many more, such as mapping editing, through the Mastro Protégé Plug-in.


The Mastro Reasoner for DL-Lite ontologies implements the common interface of ontology reasoners in Protégé, providing all required services, beginning with classification, meaning the inference of a subsumption hierarchy for the classes described in the ontology, along with satisfiability checking of the ontology and of all its elements. The Mastro Reasoner, on startup, also approximates the ontology to conform to the DL-Lite language (if necessary), and initialises the data structures that are required to perform OBDA query answering.  

The Mapping Editor allows to create, modify, and inspect a full Mastro mapping specification. Through a guided and easy-to-use interface, users can define views and mappings: the former are named SQL queries, while the latter are assertions, or rules, that link elements of the ontology to the SQL queries in the views. Through these mappings and views, the mapping specification defines the exact correspondence between the data in the sources and the classes and relations in the ontology. 

The Query Engine handles all query answering-related operations. It provides an interface to define and document SPARQL queries over the ontology, and allows to save the queries in the query catalog, through which the user can see the ontology or mapping rewriting of the selected query, execute the query and see its results, possibly exporting them to file, or delete the query from the catalog.  

Using the Plug-in

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