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From "Jay D. McHugh" <...@joyfulnoisewebdesign.com>
Subject Re: ejb 3.0--connecting to a DB
Date Wed, 20 Jun 2007 16:11:17 GMT
Viet,

Try setting:

<property name="openjpa.jdbc.SynchronizeMappings" value="false" />

I believe the default setting will rebuild your database and clear your 
tables.

As far as your data persisting, you will need to make sure you start a 
transaction and commit it after changing data.

Since you are using local transactions (in your persistence.xml), try:

em.getTransaction().begin();     // to start the transaction

and

em.getTransaction().commit();  // to close the transaction

I had the same problems when I started using JPA so hopefully that will 
work for you.


Jay
Viet Hung Nguyen wrote:
> I am deploying my db pool through the admin console. I am using the 
> tranql-connector-1.3.rar found under 
> geronimo-jetty6-jee5-2.0-SNAPSHOT\repository\org\tranql\tranql-connector-ra\1.3. 
>
>
> I am still encountering these two problems:
>
> 1) The EJB seems to be talking to the DB, but whenever I query it, the 
> data in the DB is erased.
> 2) In order to have some data in the DB I have added things to it 
> dynamically. So when I fetch the data from the DB after this addition, 
> the resultList is non-empty. However, when I try to view what I have 
> just added by casting one element of the resultant list (that is of 
> type Collection<ExchangeRate>) to an ExchangeRate object with this line:
>
>    ExchangeRate rate = (ExchangeRate)ratesList.get(i);
>
> I get a ClassCastException. Initially I thought ratesList might be 
> null, but I have ensured that it is not.
>
> For problem 1) I have read somewhere that there is a property I can 
> set so that it does not overwrite the existing data in the DB, but I 
> cannot remember what that is.
>
> As for problem 2) I am out of ideas.
>
> Thanks in advance,
> Viet Nguyen
>
>
> .
>

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