This connector stores a graph of any structure or size in a relational database, using a JPA provider on top of a JDBC driver. Currently this connector relies upon some Hibernate-specific capabilities. The schema of the database is dictated by this connector and is optimized for storing a graph structure. (In other words, this connector does not expose as a graph the data in an existing database with an arbitrary schema.)

The JpaSource class provides a number of JavaBean properties that control its behavior:

One way to configure the JPA connector is to create JcrConfiguration instance with a repository source that uses the JpaSource class. For example:

JcrConfiguration config = ...

config.repositorySource("JPA Store")

      .usingClass(JpaSource.class)

      .setDescription("The database store for our content")

      .setProperty("dialect", "org.hibernate.dialect.MySQLDialect")

      .setProperty("dataSourceJndiName", "java:/MyDataSource")

      .setProperty("defaultWorkspaceName", "My Default Workspace")

      .setProperty("autoGenerateSchema", "validate");

 

Of course, setting other more advanced properties would entail calling setProperty(...) for each. Since almost all of the properties have acceptable default values, however, we don't need to set very many of them.

Another way to configure the JPA connector is to create JcrConfiguration instance and load an XML configuration file that contains a repository source that uses the JpaSource class. For example a file named configRepository.xml can be created with these contents:

<?xml version="1.0" encoding="UTF-8"?>

<configuration xmlns:dna="http://www.jboss.org/dna/1.0" xmlns:jcr="http://www.jcp.org/jcr/1.0">

    <!-- 

    Define the sources for the content.  These sources are directly accessible using the 

    DNA-specific Graph API.  In fact, this is how the DNA JCR implementation works.  You 

    can think of these as being similar to JDBC DataSource objects, except that they expose 

    graph content via the Graph API instead of records via SQL or JDBC. 

    -->

    <dna:sources jcr:primaryType="nt:unstructured">

        <!-- 

        The 'JPA Store' repository is an JPA source with a single default workspace (though 

        others could be created, too).

        -->

        <dna:source jcr:name="JPA Store" 

                    dna:classname="org.jboss.dna.graph.connector.store.jpa.JpaSource"

                    dna:description="The database store for our content"

                    dna:dialect="org.hibernate.dialect.MySQLDialect"

                    dna:dataSourceJndiName="java:/MyDataSource"

                    dna:defaultWorkspaceName="default"

                    dna:autoGenerateSchema="validate"/>    

    </dna:sources>

    

    <!-- MIME type detectors and JCR repositories would be defined below --> 

</configuration>

 

The configuration can then be loaded from Java like this:

JcrConfiguration config = new JcrConfiguration().loadFrom("/configRepository.xml");

 

DNA users who prefer not to give DDL privileges to the DNA database user for this connector can use the DNA JPA DDL generation tool to create the proper DDL files for their database dialect. This tool is packaged as an executable jar in the utils/dna-jpa-ddl-gen subproject and can be executed with the following syntax:

java -jar <jar_name> -dialect <dialect name> -model <model_name> [-out <path to output directory>]

The dialect and model parameters should match the value of the dialect and model properties specified for the JPA connector.

Running this executable will create two files in the output directory (or the current directory if no output directory was specified): create.dna-jpa-connector.ddl and drop.dna-jpa-connector.ddl. The former contains the DDL to create or replace the tables, foreign keys, indices, and sequences needed by the JPA connector and the latter contains the DDL to drop any tables, foreign keys, indices, and sequences needed by the JPA connector.