John --

Try the MapManager tool in XML-DBMS v2 alpha 3 [1]. This allows you to 
generate a DTD from a relational database, which you could then find 
another tool to convert to an XML Schema. The major problem with this is 
that you would lose data type information. One possibility is to modify 
the code to generate Data Types for DTDs [2] -- this would be easy -- 
which could then be used to generate data types in XML Schemas.

If you want a commercial product, I suggest trying HiT Allora, which 
I've described in a list of XML / database middleware [3]. There are 
other products on the list that generate XML Schemas as well. (I point 
out Allora simply because I'm familiar with it.)

Finally, I advise you to be somewhat aware of all of these tools. While 
it is possible to generate an XML schema from a database schema, the XML 
schema is not necessarily what you want. At a minimum, the generated 
names are probably less than useful.

More problematic is that the generated structures are not necessarily 
what one might get if one set out to design an XML schema for the same 
information. For example, XML virtually encourages you to wrap things 
like address information in an Address element, while addresses in a 
database are generally flat. Another problem is how to handle 
many-to-one relationships in an XML schema.

-- Ron

[1] http://www.rpbourret.com/xmldbms/index.htm
[2] http://www.w3.org/TR/dt4dtd
[3] http://www.rpbourret.com/xml/ProdsMiddleware.htm#allora

John M Lauck wrote:

> Does anyone know if there is a freeware/opensource application that 
> generates an xml schema from a database?  (prefereably MySQL, but any is 
> fine)  I haven't found anything that specifically does this.  Most 
> applications I have come across advertise a database schema output, but 
> not necessarily an XML Schema.