Von-QBE is a Ontology-Based Query-by-Example system that operates over a relational database using a virtualized RDF Ontology. It assists the user to write queries over the database without any formal query language or previous knowledge about the database structure.

To run the application, you must have installed:

• Java 8
• Maven
• SBT
• Nodejs
• NPM

To execute this system first you need to install at your local maven repository both Linked-Graphast and RoR.

At the first time you run the system(or every time that anything is changed at the front-end), you will need to run:

./build-and-run port host

Where:

• port: the port where the application will run (default: 8080);
• host: the host where the server will run (public IP, local networl IP or localhost[default])

If you had already made one build, you can just run the server: ./run-server port

Note that the port must be the same specified at the build-and-run script, since the React front-end has been built configuring the requests to that port and host.

After the system is up, you can configure the databases and ontologies that you want to connect. To add a database, you need to upload 2 files:

• mapping file - the mappings from the ontology schema to the relational database, using Ontop syntax, and the JDBC connection parameters. You can check a example at the resources folder
• ontology schema file - the ontology schema. Now, Von-QBE supports nt, rdf, xml and owl formats.

To deploy Von-QBE on a docker container, go to the docker folder.