Re: MiddleKit Schema Upgrade

On Thu, 2006-09-07 at 09:45 -0700, Chuck Esterbrook wrote:
> On 9/7/06, Seth Remington <[email protected]> wrote:
> > Hello All,
> >
> > I am using MiddleKit in an open source application and as most projects
> > go it is expanding and evolving, and the database structure is evolving
> > with it.
> >
> > So now I have a requirement to provide a convenient upgrade path for
> > users that includes database schema changes. MiddleKit is wonderful for
> > doing a fresh install... but not so much for upgrading an existing
> > install.
> >
> > I've researched the archives and wiki and found the references to
> > mysqldiff. Unfortunately I can't guarantee that other users are going to
> > be using MySQL so the resulting SQL might not be portable.
> >
> > I'm thinking I might have to write something to use the MiddleKit.Design
> > internals to generate the appropriate SQL for the appropriate database.
> > But before I delved into that I thought I would ask the community if
> > anyone has dealt with this situation before, or perhaps a better
> > suggestion about how to go about it.
> >
> > -Seth
> 
> Hi Seth,
> 
> Everytime I've dealt with this situation, I have used mysqldiff,
> pgdiff or RedGate SQL Compare. So always the same approach, just a
> different tool depending on the database.
> 
> You certainly could write a program that would load an old MK model
> and a current model and then generate the statements to turn the old
> into the new. Of course, the user will have to ensure that they feed
> the correct old model that matches their current
> database-to-be-updated. I feel that could be error prone and/or
> burdensome which is why I went the "sql schema diff" route. Plus it
> saves time to leverage them.
> 
> But if you did write an MK-update utility, it would be along the lines
> of loading the two models and then enumerating the Klasses and Attrs
> inside to determine what had to be added, removed or altered. MK
> models are comprised of objects from the classes seen in
> MiddleKit/Core/*.py. The code in MiddleKit/Design certainly shows
> examples of plowing through the contents of a model. And yeah, you
> would leverage it for any CREATE statements you needed to generate.
> You'd have to write the ALTERs and removals yourself.
> 
> If you have more MK questions, feel free.
> 
> -Chuck

Thanks Chuck. I'm going to ponder this a bit more. You've given me a good head start.

-Seth
-- 
Seth Remington <[email protected]>


-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642