Database for storing heterogeneous "message" objects

[Roberto Lupi]

In article <I4qn4.20005$3b6.85771 at ozemail.com.au>, 
jstok at bluedog.apana.org.au says...
> I want to use a database to store sets of heterogeneous "message" objects,
> which currently cover email and news messages, but will be extended more
> generally to include messages in web-accessible archives and other
> "email-like" things.  Queries can be made on a message database based on
> their header properties.

You can use ZODB, the OODBMS that is the basis of Zope - IMHO it fits 
your requirements nicely.

> defined for all messages.  I want to allow queries on optional headers -- if
> a header is defined for a message, any selection rule based on that message
> will be applied to it, otherwise the test automatically fails.

You can use ZCatalog.

-- 
Roberto Lupi