Inject property into JPA orm.xml? - orm

Question

We are splitting our baseline (for release 1.0 and 2.0 concurrent development). Instead of maintaining two separate databases (and hardware), we are investigating other alternatives. We would like to be able to use the same instance of a database, and have duplicate copies of the tables/data in two different schemas:
1.0: SCHEMA_1
2.0: SCHEMA_2
The JPA orm.xml file has a property where the schema is specified:
<schema>SCHEMA_1</schema>
My question is whether a property can be injected instead of a hard coded schema name (and how).
For example, if we have a .properties file with the following:
schema.name=SCHEMA_1
Can we then use schema.name in the orm.xml file like this:
<SCHEMA>schema.name</SCHEMA>
Thanks for any help! Other alternatives for making the schema dynamic are also welcome.

Answer 1

JPA only defines this in the orm.xml.
In EclipseLink you can use a SessionCustomizer to set this on your EclipseLink Session in code,
session.getLogin().setTableQualifier("SCHEMA_1");

Answer 2

We ended up using the velocity-maven-plugin to replace tags for the schema at build-time.
In orm.xml template:
<schema>${schemaName}</schema>
In the pom file:
<plugin>
<groupId>net.rumati.maven.plugins</groupId>
<artifactId>velocity-maven-plugin</artifactId>
<version>0.1.1</version>
<executions>
<execution>
<id>replaceSchema</id>
<phase>generate-sources</phase>
<goals>
<goal>velocity</goal>
</goals>
</execution>
</executions>
<configuration>
<template>${basedir}/src/main/resources/hibernate/template/orm.xml</template>
<properties>
<schemaName>${r1Schema}</schemaName>
</properties>
<outputFile>${basedir}/src/main/resources/hibernate/orm.xml</outputFile>
</configuration>
</plugin>

Answer 3

I've been faced with the exact problem. Instead of building the orm.xml in to the project, leave it out of the artifact build. Then at runtime, put it on the classpath of the application so it's picked up:
<persistence-unit-metadata>
<persistence-unit-defaults>
<schema>MySchemaThatsBeenDeterminedAtRuntime</schema>
</persistence-unit-defaults>
</persistence-unit-metadata>
Each instance of application can have it's own orm.xml and point to a different schema.