[Zope] What's involved in writing a DA (for Ingres)?

I'd like to have a Zope DA for Ingres II (on Solaris), and since I haven't come across an existing one, I'm thinking of attempting to write my own (!), building it on top of a DB-API-compliant Python module for Ingres that I've got hold of. I've grabbed the "How to Write a DA" document; is there anything else that would be useful? Are there any particular existing DAs that it would be worthwhile to look at for guidance? Hamish Lawson ____________________________________________________________ Do You Yahoo!? Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk or your free @yahoo.ie address at http://mail.yahoo.ie