Using Teiid with Hibernate

Configuration

For the most part, interacting with Teiid VDBs (Virtual Databases) through Hibernate is no different from working with any other type of data source.  First, depending on where your Hibernate application will reside, either in the same VM as the Teiid Runtime or on a separate VM, will determine which jar’s are used.

  • Running in same VM in the WildFly server, then the teiid-client-{version}.jar and teiid-hibernate-dialect-{version}.jar already reside in <jboss-install>/modules/org/jboss/teiid/client

  • Running separate VM’s,you need the Teiid JDBC Driver JAR and Teiid’s Hibernate Dialect JAR in the Hibernate’s classpath.  The Hibernate JAR can be found in <jboss-install>/modules/org/jboss/teiid/client, teiid-hibernate-dialect-{version}.jar and the Teiid JDBC Driver JAR needs to be downloaded.

These JAR files have the org.teiid.dialect.TeiidDialect and org.teiid.jdbc.TeiidDriver and org.teiid.jdbc.TeiidDataSource classes.

You configure Hibernate (via hibernate.cfg.xml) as follows:

  • Specify the Teiid driver class in the connection.driver_class property:

<property name="connection.driver_class">
     org.teiid.jdbc.TeiidDriver
</property>

  • Specify the URL for the VDB in the connection.url property (replacing terms in angle brackets with the appropriate values):

<property name="connection.url">
    jdbc:teiid:<vdb-name>@mm://<host>:<port>;user=<user-name>;password=<password>
</property>
Tip
 Be sure to use a Local JDBC Connection if Hibernate is in the same VM as the application server.

  • Specify the Teiid dialect class in the dialect property:

<property name="dialect">
    org.teiid.dialect.TeiidDialect
</property>

Alternatively, if you put your connection properties in hibernate.properties instead of hibernate.cfg.xml, they would look like this:

hibernate.connection.driver_class=org.teiid.jdbc.TeiidDriver
hibernate.connection.url=jdbc:teiid:<vdb-name>@mm://<host>:<port>
hibernate.connection.username=<user-name>
hibernate.connection.password=<password>
hibernate.dialect=org.teiid.dialect.TeiidDialect

Note also that since your VDBs will likely contain multiple source and view models with identical table names, you will need to fully qualify table names specified in Hibernate mapping files:

<class name="<Class name>" table="<Source/view model name>.[<schema name>.]<Table name>">
    ...
</class>
Example Mapping
<class name="org.teiid.example.Publisher" table="BOOKS.BOOKS.PUBLISHERS">
    ...
</class>

Identifier Generation

  • Identifier generation based upon table values, such as the hilo generator, require that the identifier table(s) be exposed through Teiid.

  • GUID and Identity (using generated key retrieval) identifier generation strategy are directly supported.

Limitations

  • Many Hibernate use cases assume a data source has the ability (with proper user permissions) to process Data Definition Language (DDL) statements like CREATE TABLE and DROP TABLE as well as Data Manipulation Language (DML) statements like SELECT, UPDATE, INSERT and DELETE. Teiid can handle a broad range of DML, but does not directly support DDL against a particular source.

  • Sequence generation is not directly supported.

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