Re: Evolution of the model or schema

Hello, Alejandro.

Thanks for your fast response.

Your approach makes sense to me. Just to make sure, I got it right,
I'll sum it up using my own words. You recommend to
  * use the full Trails stack, including hibernate, to create a first version.
  * exclude hibernate from Trails' stack and configure it properly
  * manually keep the hibernate xml and the migration sql in sync
with the remaining Trails app

Did I get that right?

Regards,
Daniel

2008/4/16, Alejandro Scandroli <alejandroscandroli@...>:

> Hi Daniel
>
>  The problem reduces to how hibernate handles the entity model evolution.
>  I tell you what I do.
>  To be able to control evolution I like to get more control over the
>  hibernate configuration
>  So:
>  I remove the apt-plugin from the pom, so now I'm responsible for
>  (manually) maintaining hibernate.cfg.xml up to date.
>  I remove the custom "resources" declaration from the pom to go back to
>  standard maven.
>  I change hibernate.hbm2ddl.auto=update to
>  hibernate.hbm2ddl.auto=validate, this way hibernate won't screw up my
>  DB without me noticing it, so now I'm responsible for manually
>  upgrading my DB.
>  I generate the first schema ddl using the maven hibernate plugin.
>  I load the schema to my DB.
>  I use a dump utility to extract a dump of my empty DB.
>  And this is my starting point, let's called version 1
>  DEPLOY
>  After this, every change in the entity model is accompanied with the
>  corresponding sql script to handle the DB upgrade, migrate_v1_v2.sql
>  When the version 2 deployment time comes, I upgrade my DB using
>  migrate_v1_v2.sql, I create a new dump (version2.dump.sql)  and I
>  start a new upgrade script: migrate_v2_v3.sql
>
>  I know this is not as "agile" as when you start with Trails, but is
>  the best way I know to handle this kind of situations. If anyone know
>  a different ways please let me know.
>
>  Trails will accommodate to the entities changes, of course that if you
>  rename an entity that has custom pages you will need to rename the
>  custom pages too, but in general it will work.
>
>  I hope it helps.
>  Saludos.
>  Alejandro.
>
>  --
>  Alejandro Scandroli - http://weblog.amneris.es/
>  Amneris: We build process-driven web applications.
>  http://www.amneris.es
>
>
>
>
>
>
>  On Wed, Apr 16, 2008 at 9:51 AM, Daniel Lauk <daniel.lauk@...> wrote:
>  > Hello, list.
>  >
>  >  I am doing evaluations of (web) app frameworks at work.
>  >  I played around with trails and found it very interesting. But one
>  >  certain point at issue is not answered in the docs.
>  >
>  >  How does Trails cope with the natural evolution process every software
>  >  goes through (e.g. an enum is refactored into an own class)?
>  >  Is there a recommended strategy for coping with that?
>  >
>  >  Of course, when there is no data yet (before the first release), it's
>  >  trivial. Just wipe out the database and start from scratch. But what
>  >  if there is data to be migrated?
>  >
>  >  Kind regards,
>  >  Daniel
>  >
>
> >  ---------------------------------------------------------------------
>  >  To unsubscribe from this list, please visit:
>  >
>  >     http://xircles.codehaus.org/manage_email
>  >
>  >
>  >
>
>  ---------------------------------------------------------------------
>  To unsubscribe from this list, please visit:
>
>     http://xircles.codehaus.org/manage_email
>
>
>

---------------------------------------------------------------------
To unsubscribe from this list, please visit:

   http://xircles.codehaus.org/manage_email