Thanks a lot Andrei and Reinhard.
I asked the query below in order
to understand the logic eclipselink handles sequence generation. I am planning
to introduce our own sequence generator since we need IDs to be generated
upfront before an entity is attached to the em.
I have an option to do this
using spring jdbc. However being new to Spring JDBC I am unable to think of a
similar implementation using Spring JDBC template wherein I can update
preceding select and execute them both in the same transaction.
Can somebody please throw some
light?
Regards,
Shashi
From: eclipselink-users-bounces@xxxxxxxxxxx
[mailto:eclipselink-users-bounces@xxxxxxxxxxx] On Behalf Of Andrei
Ilitchev
Sent: Tuesday, July 20, 2010 11:24 PM
To: EclipseLink User Discussions
Subject: Re: [eclipselink-users] Question on sequencing using
TableGenerator
In table sequence case, update precedes select and both are
executed in the same transaction - so no dirty reads can happen.
On 20/07/2010 12:49 PM, Shashikant Kale wrote:
Hi,
We have been using eclipselink and I have a question wrt
eclipselink in clustered environment. We are using TableGenerator for
generating primary keys and we use the same sequence for all the entities.
e.g.
@GeneratedValue(strategy =
GenerationType.TABLE, generator = "default")
@TableGenerator(
name = "default",
table = "ID_GENERATOR",
pkColumnName = "ID_NAME",
valueColumnName = "ID_VALUE",
pkColumnValue = "default",
initialValue = 1,
allocationSize = 50
)
However I have found that the Select query is fired without
“For Update” clause. Wouldn’t this cause issues due to dirty reads across
multiple JVMs?
Kindly let me know how this is taken care.
Thanks,
Shashi
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