There are definitely some limitations to the workarounds.
You could define a number of persistence units in your persistence.xml that use
the same classes and metadata.
-Tom
Daniel Benítez wrote:
> Hi Tom,
>
> How I can create multiple versions of my persistence unit? with physical
> files? I can't do that because I must connect with a lot of data base.
>
> Daniel Benítez.
>
>
> --------------------------------------------------
> From: "Tom Ware" <tom.ware_at_oracle.com>
> Sent: Friday, July 04, 2008 3:28 PM
> To: <persistence_at_glassfish.dev.java.net>
> Subject: Re: two connections with a persistence unity
>
>> Hi Daniel,
>>
>> At the moment, TopLink Essentials does not support using connections
>> that are defined differently within the same EntityManagerFactory.
>> Here is the Issue Tracker issue that tracks this feature request:
>>
>> https://glassfish.dev.java.net/issues/show_bug.cgi?id=1575
>>
>> The workaround is to create multiple versions of your persistence
>> unit and use different login information for each.
>>
>> -Tom
>>
>> Daniel Benítez wrote:
>>> Hey everybody, We need help!!!
>>>
>>> For a connection with a Derby data base we are using a glassfish
>>> persistence unit. For that, we have created that persistence unit
>>> through
>>> Netbeans and with:
>>>
>>> protected EntityManager em;
>>> private static EntityManagerFactory emf;
>>>
>>> Properties databaseProperties = new Properties();
>>>
>>> databaseProperties.setProperty(oracle.toplink.essentials.config.TopLinkProperties.JDBC_URL,
>>> jdbcUrl);
>>>
>>> databaseProperties.setProperty(oracle.toplink.essentials.config.TopLinkProperties.JDBC_DRIVER,
>>> "org.apache.derby.jdbc.ClientDriver");
>>>
>>> databaseProperties.setProperty(oracle.toplink.essentials.config.TopLinkProperties.JDBC_USER,
>>> Usuario);
>>>
>>> databaseProperties.setProperty(oracle.toplink.essentials.config.TopLinkProperties.JDBC_PASSWORD,
>>> Contrasenya);
>>>
>>> emf = Persistence.createEntityManagerFactory(Manejador,
>>> databaseProperties);
>>> em = emf.createEntityManager( );
>>>
>>> as a code.
>>>
>>> The problem is that when we want to change the initial data base (using
>>> for that, destroy funtion (
>>>
>>> public void destruir(){
>>> em.clear();
>>> em.close();
>>> em = null;
>>> emf.close();
>>> //emf = null;
>>> }
>>>
>>> ) eliminating the class and establishing a new
>>> connection for this new data base ¡we always obtain a connection
>>> with the
>>> initial data base!!!
>>>
>>> What are we doing wrongly ?
>>>
>>> Is it possible to connect an unique persistence unit to different data
>>> base? How?
>>>
>>> Thanks very much for the help
>>