Wt

On a related issue, I'm wondering how schema changes are managed when pushing out changes in a project database that has a lot of activity. What is the protocol for backing up data, rolling out changes with Wt:dbo, and then importing data back in without problems? It would be nice to have a utility for this incorporated into Wt:dbo. It obviously couldn't accommodate every conceivable scenario, but it would be a great productivity tool if it just allowed data import and export a part of deployments. Perhaps managing some of the most common use cases and providing for reporting of any database errors that arise during usage.

Hey,

In practice, there is a database migration that is needed, which usually involves a SQL script that performs an upgrade (without needing to export/reimport all data). Such a migration task would be nice to have, but isn't straight-forward at all (for example you need to specify a default value for a non-null column that you are adding) and usually such a SQL script first relaxes constraints, completes the data, and then (re-)adds constraints.

The first step would need to be the ability for Wt::Dbo to read the current schema and decide what the differences are, or, put database-version information in some auxiliary table. I'm not sure any approach has particular benefits but again it's something that will be food for discussion as soon as we would implement one or the other method.

Regards,

koen

I haven't used Rails but do know that it allows rollback to previous version, including synchronization with the database. I'd imagine that there is also some facility for managing database during updates. Might be a good place to go for ideas, not sure. It is just that with the database object model, if some change is made to the model, it would be a nice efficiency if some of those changes were automated or handled by the library. For instance, a change to datatype of a field might cause an update statement to be run on the database. That sort of thing.