[jbpm-dev] Re: jbpm-3.3.0 backward compatibility

[Alejandro Guizar]

Indeed, we made some changes that will benefit new jBPM deployments but
might pose potential problems to existing installations. We know for a
fact that some of our customers are willing to undergo such changes, but
it could take others by surprise.

At least some databases allow string (varchar) columns to be
read/written as character streams (text) so the actual impact may be
less than we think. Of course we would have to test our targets
databases one by one before making any assertions.

That said, our old mappings never really worked for Sybase, so no danger
about incompatibility there :)

-Alejandro

El mar, 11-11-2008 a las 13:19 +0100, Tom Baeyens escribió:
> that is not safe to say in general.  this is exactly why we were working on rolling 
> back the hibernate string/text changes, which eventually didn't make it in the release.
> 
> it depends on how the text hibernate mappings translate to the user's specific 
> database.  for some databases this will work transparant.  for others, they might 
> need to change the type of some of their database columns.
> 
> this is why i added a reference at the last minute yesterday on how to revert those 
> hibernate mapping changes.
> 
> also one column needs to be added to a table.
> 
> the lesson we learned is that hibernate mapping updates should be monitored much more 
> closely.  e.g. with a continuous integration test.
> 
> this is a topic that we should talk about next meeting: we could introduce a job that 
> runs the test suite by starting from the previous database schema and running the 
> schema update script.  then if someone introduces a db schema change, first, there is 
> a signal if this happens unexpectedly, secondly the developer is forced to also 
> update the DB migration scripts which means that we'll have db migration as part of 
> the development.
> 
> regards, tom.
> 
> 
> Thomas Diesler wrote:
> > Folks,
> > 
> > is it save to say that 3.3.0 is backward compatible with 3.2.2?
> > 
> > If this is true, I can advise a component update for the SOA-P and there 
> > would not need to be any work on the so jBPM SOA branches needed.
> > 
> > cheers
> > -thomas