# D2RQ – A Database to RDF Mapper D2RQ exposes the contents of relational databases as RDF. It consists of: * The **D2RQ Mapping Language**. Use it to write mappings between database tables and RDF vocabularies or OWL ontologies. * The **D2RQ Engine**, a SPARQL-to-SQL rewriter that can evaluate SPARQL queries over your mapped database. It extends ARQ, the query engine that is part of Apache Jena. * **D2R Server**, a web application that provides access to the database via the SPARQL Protocol, as Linked Data, and via a simple HTML interface. ## Homepage and Documentation Learn more about D2RQ at its homepage: http://d2rq.org/ ## License Apache License, Version 2.0 http://www.apache.org/licenses/LICENSE-2.0.html ## Contact, feedback, discussion Please use the issue tracker here on GitHub for feature/bug discussion and support requests. ## Building from source ### Prerequisites You need some tools in order to be able to build D2RQ. Depending on your operating system, they may or may not be already installed. * [git](http://git-scm.com/), for forking the source code repository from GitHub. Run `git` on the command line to see if it's there. * [Java JDK](http://www.oracle.com/technetwork/java/javase/downloads/index.html) v5 or later, for compiling Java sources. Run `java -version` and `javac` on the command line to see if it's there. * [Apache Ant](http://ant.apache.org/), for building D2RQ. Run `ant` on the command line to see if it's there. ### Getting the source Get the code by forking the GitHub repository and cloning your fork, or directly clone the main repository: ```git clone git@github.com:d2rq/d2rq.git``` ### Doing Ant builds D2RQ uses Apache Ant as its build system. You can run `ant -p` from the project's main directory to get an overview of available targets: To run the D2RQ tools, you need to do at least `ant jar`. <table> <tr><td>ant all</td><td>Generate distribution files in zip and tar.gz formats</td></tr> <tr><td>ant clean</td><td>Deletes all generated artefacts</td></tr> <tr><td>ant compile</td><td>Compile project classes</td></tr> <tr><td>ant compile.tests</td><td>Compile test classes</td></tr> <tr><td>ant jar</td><td>Generate project jar file</td></tr> <tr><td>ant javadoc</td><td>Generate Javadoc API documentation</td></tr> <tr><td>ant tar</td><td>Generate distribution file in tar.gz format</td></tr> <tr><td>ant test</td><td>Run tests</td></tr> <tr><td>ant vocab.config</td><td>Regenerate Config vocabulary files from Turtle source</td></tr> <tr><td>ant vocab.d2rq</td><td>Regenerate D2RQ vocabulary files from Turtle source</td></tr> <tr><td>ant war</td><td>Generate war archive for deployment in servlet container</td></tr> <tr><td>ant zip</td><td>Generate distribution file in zip format</td></tr> </table> ## Running D2RQ After building with `ant jar`, you can test-run the various components. Let's assume you have a MySQL database called `mydb` on your machine. ### Generating a default mapping file ```./generate-mapping -u root -o mydb.ttl jdbc:mysql:///mydb``` This generates a mapping file `mydb.ttl` for your database. ### Dumping the database ```./dump-rdf -m mydb.ttl -o dump.nt``` This creates `dump.nt`, a dump containing the mapped RDF in N-Triples format. ### Running D2R Server ```./d2r-server mydb.ttl``` This starts up a server at http://localhost:2020/ ### Deploying D2R Server into a servlet container Edit `/webapp/WEB-INF/web.xml` to point the `configFile` parameter to the location of your mapping file. Build a war file with `ant war`. Deploy the war file, e.g., by copying it into the servlet container's `webapps` directory. ### Running the unit tests The unit tests can be executed with `ant test`. Some unit tests rely on MySQL being present, and require that two databases are created: 1. A database called `iswc` that contains the data from `/doc/example/iswc-mysql.sql`: echo "CREATE DATABASE iswc" | mysql -u root mysql -u root iswc < doc/example/iswc-mysql.sql 2. An empty database called `D2RQ_TEST`.