[SQLObject] sqlobject-admin == ruby-on-rails migrations?

[Christian W. <cw...@tu...>]

Hi all,


in the past I've worked on some projects using ruby-on-rails. I found 
the "migrations" framework very useful, that allows to 
semi-automatically keep track of an evolving database scheme.

In particular, I am facing the following problem. I have a class 
definition, which also defines my database scheme. By now I have already 
generated a number of datasets which populate latter database. The 
problem now is that I need additional fields in my database. I see two 
obvious solutions to this:

1) drop and recreate database with new scheme
2) manually alter my tables according to my class definitions

1) is not an option, and I would like to avoid going with 2) every time 
I need to add a column. As mentioned before, ruby-on-rails provides some 
tools to update a database scheme semi-automatically, once the 
corresponding class definition has been changed. A google search pointed 
me to a tool called sqlobject-admin, which seems to be able to do 
something similar.
However, from the documentation 
(http://www.sqlobject.org/sqlobject-admin.html), it was not obvious to 
me how to achieve this.

"sqlobject-admin upgrade -h" says:
This command runs scripts (that you write by hand) to upgrade a database....

Does this mean, that I end up having to manually update the table 
definition AND the class definition each time? Is there no way to create 
a "diff" between the class defined in python and the current database 
scheme automatically?


Help would be appreciated,
Chris