[gentoo-server] Request for Comments: dbdeploy eclass

[Bishop Bettini]

dbdeploy is a strategy for migrating a database from earlier to later  
versions through the use of delta SQL files.  Originally implemented  
for Java, with a later evolution in Phing, PEAR, and .NET, the  
strategy is documented at:
http://dbdeploy.com/documentation/

Each delta has a change number, and when that numbered changed is  
applied to a given DB, the number is remembered in a changelog table.   
Thus, a change will be applied only once, to a given database, and the  
history of applied changes can be easily queried within the database  
itself.

Lots of applications have SQL that should be applied to the database.   
Those that do not already have a SQL migration practice inherent in  
their architecture often rely on ad-hoc means to upgrade a database.   
This leads wheels being reinvented, despite an established practice  
being available.  A dbdeploy eclass would help these applications  
standardize on a means to apply SQL changes should their deployment  
environment not already provide one.

We have developed a dbdeploy eclass to allow ebuilds to apply database changes
from within the ebuild.  Our prototype implementation has concrete support for
generic/vanilla SQL (known to work on MySQL and PostgreSQL), but the  
design allows for plugging in specific DBMS syntax.

Our initial implementation is attached.

As you can see, the eclass is not concerned with the mechanics of  
reading from or writing to the database.  That is package-dependent  
and is left to the package to implement.  The eclass provides only the  
SQL necessary to list the changes applied so far and the SQL to apply  
changes from a given directory, as well as support for undoing failed  
changes.

Is this something the Gentoo community would be interested in having  
available?

thoughts?

Thanks!
bishop

-- 
Bishop Bettini
ideacode, Inc.
(main) [phone] / (fax) [phone]

Visit us on the web at:
ideacode.com          Professional software research and development
reviewmysoftware.com  Improve sales! Review your software before you release
bytejar.com           Solutions to those annoying development problems