persistence.xml

In my projects I often use JPA/Hibernate stack for database. When defining persistence.xml you have couple options you can set hibernate.hbm2ddl.auto . If set to create tables will be recreated on every application run (persisted data will be lost of course). It is also possible to import initial data by setting db fixture with hibernate.hbm2ddl.import_files . When set to update only tables for new entities will be created (persisted data in existing tables will be preserved). The thing is that this is not that convenient while developing and I'd like behavior like this: on first application

I am trying to understand the following things: When I make an EJB project and deploys it to Glassfish do I set up JDBC resources/connection pools at the administrator center of Glassfish or do I add all the different properites for username, password etc in the persistence.xml? I don't understand one bit of that. I do not understand why we have both JDBC resource and JDBC Connection pool either. What is it and what is the difference between them? Could somebody explain me these things or/and provide some good link about the persistence.xml file and the part around it? It's better to define a

The parameter unreturnedConnectionTimeout times out unreturned connections after a given period of time. I'm trying to decide whether I should use this in my production persistence.xml ? A big plus of using this is that the Connection Pool will be able to recover from leaky connections. A big minus is that leaky connections will be very difficult to detect. Should I use unreturnedConnectionTimeout in production applications? If yes, what should its value be? Are there any other pros/cons I should consider? Steve Waldman You should debug your Connection leaks, and then not use

Is it possible to have two persistence units in a Wildfly (9.0.2) application? I get "WFLYJPA0061: Persistence unitName was not specified and there are 2 persistence unit definitions in application deployment deployment "jasper-web.war". Either change the application deployment to have only one persistence unit definition or specify the unitName for each reference to a persistence unit." I have unitName specified in the @PeristenceContext annotations. I read somewhere I could disable <!-- <subsystem xmlns="urn:jboss:domain:jpa:1.1"> <jpa default-datasource="" default-extended-persistence