NHibernate concurrency with Oracle's ORA_ROWSCN

ORA_ROWSCN behavior: bug or feature?

NHibernate concurrency with Oracle's ORA_ROWSCN

JuanCho — Wed, 03 Jun 2009 13:08:32 GMT

Revision 4 posted to How to by JuanCho on 03/06/2009 10:08:32 a.m.

NHibernate concurrency with Oracle's ORA_ROWSCN

Filed under: Mapping, Nhibernate, Oracle, Concurrency, Version, property

I'm just starting to get my feet wet with NHibernate and one of the topics that popup here at the bar (you are thinking about NH when you have a couple of cold ones, aren't you? [B]) B] ) was if we could use something like sql server's timestamp column to handle concurrency with NH and Oracle.

SQL Server's Timestamp column is not datetime as you might think, but an 8 byte binary that is changed any time that the row is updated.

Back at the office, I started researching and it figures out that Oracle (v9 or greater) provides its own flavor of this feature: welcome to ORA_ROWSCN.

This is a lot of prose for such little code, below are the configuration entries that your hbm files should have in order to use the version feature with NH.

NH 2.0:

NH 2.1 (above syntax seems to also work with NH 2.1, this is just a variation)

</version>

I hope this saves someone, a couple hours of googling.

NOTE: The usage of ORA_ROWSCN will incur on an extra db call (SELECT ORA_ROWSCN...) during INSERTS/UPDATES since its value is updated on COMMIT. In Nhibernate, this means that after the entity was modified, the version property won't have a valid value until a Flush() has been issued and a Refresh() has been performed.

NH does a Refresh(), but it seems to do it (during Save()) before the Flush() (COMMIT), forcing to explicitly call a Refresh() afterward.

Some references:

ORA_ROWSCN behavior: bug or feature?

NHibernate concurrency with Oracle's ORA_ROWSCN

JuanCho — Wed, 29 Apr 2009 19:54:07 GMT

Revision 3 posted to How to by JuanCho on 29/04/2009 04:54:07 p.m.

NHibernate concurrency with Oracle's ORA_ROWSCN

Filed under: Mapping, Nhibernate, Oracle, Concurrency, Versionmapping , property

I'm just starting to get my feet wet with NHibernate and one of the topics that popup here at the bar (you are thinking about NH when you have a couple of cold ones, aren't you? [B]) was if we could use something like sql server's timestamp column to handle concurrency with NH and Oracle.

SQL Server's Timestamp column is not datetime as you might think, but an 8 byte binary that is changed any time that the row is updated.

Back at the office, I started researching and it figures out that Oracle (v9 or greater) provides its own flavor of this feature: welcome to ORA_ROWSCN.

This is a lot of prose for such little code, below are the configuration entries that your hbm files should have in order to use the version feature with NH.

NH 2.0:

NH 2.1 (above syntax seems to also work with NH 2.1, this is just a variation)

</version>

I hope this saves someone, a couple hours of googling.

Some references:

NHibernate concurrency with Oracle's ORA_ROWSCN

JuanCho — Wed, 29 Apr 2009 19:54:07 GMT

Revision 2 posted to How to by JuanCho on 29/04/2009 04:54:07 p.m.

NHibernate concurrency with Oracle's ORA_ROWSCN

Filed under: Nhibernate, Oracle, Concurrency, Version mapping property

I'm just starting to get my feet wet with NHibernate and one of the topics that popup here at the bar (you are thinking about NH when you have a couple of cold ones, aren't you? [B]) was if we could use something like sql server's timestamp column to handle concurrency with NH and Oracle.

SQL Server's Timestamp column is not datetime as you might think, but an 8 byte binary that is changed any time that the row is updated.

Back at the office, I started researching and it figures out that Oracle (v9 or greater) provides its own flavor of this feature: welcome to ORA_ROWSCN.

This is a lot of prose for such little code, below are the configuration entries that your hbm files should have in order to use the version feature with NH.

NH 2.0:

NH 2.1 (above syntax seems to also work with NH 2.1, this is just a variation)

</version>

I hope this saves someone, a couple hours of googling.

Some references:

NHibernate concurrency with Oracle's ORA_ROWSCN

JuanCho — Wed, 29 Apr 2009 19:51:27 GMT

Revision 1 posted to How to by JuanCho on 29/04/2009 04:51:27 p.m.

I'm just starting to get my feet wet with NHibernate and one of the topics that popup here at the bar (you are thinking about NH when you have a couple of cold ones, aren't you? [B]) was if we could use something like sql server's timestamp column to handle concurrency with NH and Oracle.

SQL Server's Timestamp column is not datetime as you might think, but an 8 byte binary that is changed any time that the row is updated.

Back at the office, I started researching and it figures out that Oracle (v9 or greater) provides its own flavor of this feature: welcome to ORA_ROWSCN.

This is a lot of prose for such little code, below are the configuration entries that your hbm files should have in order to use the version feature with NH.

NH 2.0:

NH 2.1 (above syntax seems to also work with NH 2.1, this is just a variation)

</version>

I hope this saves someone, a couple hours of googling.

Some references: