Configuring two resource reference files on the same data source
You can configure two resource reference files on the same data source. This allows you to extend the custom properties for the data source to be extended to include two different schema names (currentSQLId on z/OS® or currentSchema name in the custom properties) that can be used to exploit the capabilities of the application server.
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property name="openjpa.jdbc.TransactionIsolation" value="read-committed"
In order to satisfy this request, Java™ Persistence API (JPA)
will obtain a connection and immediately call setTransactionIsolation(READ_COMMITTED). When
you have two EntityManagers share a single physical connection to the database, the first
EntityManager creates a connection to the database and involves that connection in a transaction.
When the second EntityManager creates a connection, it is not able to change the isolation level.
You can avoid this problem by creating two resource reference files in the same data source. You
can create the resource references with Rational®
Application Developer or by editing the XML files. You will need to make changes to the
ejb-jar.xml, ibm-ejb-jar-bnd.xml, ibm-ejb-jar-ext.xml,
persistence.xml files.
Note: For IBM®
Optim™ PureQuery Runtime, if this is an XA data source you
must define a new custom property on the data source where property_name =
downgradeHoldCursorsUnderXa and boolean value =
true.
See the following sections for information on how to accomplish this: