[storm] ORM-agnostic schema migration

[Jamu Kakar]

Hi Daniel,

On Tue, Aug 18, 2009 at 10:54 AM, Daniel
Werner<daniel.d.werner at googlemail.com> wrote:
> What I'm looking for is a software to compare multiple database
> schemas (e.g., an original and a slightly modified version) and create
> patches" (basically SQL scripts) which can be used to upgrade old
> database schemas to the changed version. Does anyone of you already
> use a tool like this? I'm hopeful that something like this may already
> be employed at Canonical, since you seem to prefer schema management
> via pure SQL.

What we do on the Landscape team is to write patches that apply
changes to our schemas.  IOW, we don't rely on any automated
comparison of schemas.  Each database has a 'patch' table with a
single 'version' column.  We check to see that all patch versions
the software knows about have a corresponding row in the 'patch'
table.  If any of the version numbers aren't in the 'patch' table we
apply patch to bring the database schema to the required state.

Thanks,
J.