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From Jean-Baptiste BRIAUD -- Novlog <j-b.bri...@novlog.com>
Subject Re: relationship EntityManager and JDBC Connection?
Date Mon, 28 Sep 2009 08:53:30 GMT
OK, so is there a way to have add pool behavior with only JDBC  
(without J2EE) ?


On Sep 28, 2009, at 05:04 , C N Davies wrote:

> The doc says:
>
> "EntityManagerFactory instances are heavyweight objects. Each  
> factory might
> maintain a metadata cache, object state
> cache, EntityManager pool, connection pool, and more."
>
> "2.6.3. openjpa.jdbc.DriverDataSource
> Property name: openjpa.jdbc.DriverDataSource
> Configuration API:
> org.apache.openjpa.jdbc.conf.JDBCConfiguration.getDriverDataSource
> Resource adaptor config-property: DriverDataSource
> Default: pooling"
>
> "In its default configuration, OpenJPA obtains JDBC connections on an
> as-needed basis. OpenJPA EntityManagers do not retain
> a connection to the database unless they are in a datastore  
> transaction or
> there are open Query results that are using a live
> JDBC result set. At all other times, including during optimistic
> transactions, EntityManagers request a connection for each
> query, then immediately release the connection back to the pool."
>
>
> -----Original Message-----
> From: Christopher Giblin [mailto:CGI@zurich.ibm.com]
> Sent: Monday, 28 September 2009 1:11 AM
> To: users@openjpa.apache.org
> Subject: relationship EntityManager and JDBC Connection?
>
>
> Hi,
>
> Does an EntityManager instance correspond one-to-one to a JDBC  
> connection?
> When the EM is closed, is the JDBC connection closed? That is, by  
> opening
> and closing EMs, is one also opening and closing JDBC connections?
>
> I am using OpenJPA with Derby. There is no connection pooling:
>
> <property name="openjpa.ConnectionDriverName" value=
> "org.apache.derby.jdbc.ClientDriver"/>
>
> Sorry if I overlooked in the excellent documentation.
>
> Thanks,chris
>
>


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