Just for the record (from an email I sent to the dev mailing list)
a) Tom Dudziak of ddlutils (http://db.apache.org/ddlutils/) has created a
kind of "base xsd" in ddlutil's svn
which is intended for using ddlutils together with a torque schema. It was
an idea that Torque might use ddlutils at some point in the future, so if
there is an xsd, I'd rather have it extend ddlutil's xsd.
b) I am concerned about possible differences between xsd and dtd. My
personal feeling is that we should either have an xsd or a dtd.
referring to b), some people wrote that they'd rather have an xsd than a dtd