In some situations it is good to include dates or version numbers in
namespace names. 
For example, if your maintenance/governance arrangement expects new
versions, and particularly if the new versions are not compatible with older
versions. 
Geography Markup Language from OGC made the mistake of keeping the same XML
namespace for several incompatible versions of GML, and this has caused
confusion. (The policy has since been fixed). 

Of course, you can choose to give your new version a completely new name and
namespace, but sometimes you want to claim continuity, or at least a common
scope, with an earlier product, but not confuse processors by having
incompatible declarations in the same target namesapce. 

There are no universal rules here - you need to be clear about your
application and requirements. 


--------------------------------------------------------
Simon Cox

European Commission, Joint Research Centre, 
Institute for Environment and Sustainability, 
Spatial Data Infrastructures Unit, TP 262 
Via E. Fermi, 2749, I-21027 Ispra (VA), Italy 
Tel: +39 0332 78 3652
Fax: +39 0332 78 6325
mailto:simon.cox@j... 
http://ies.jrc.ec.europa.eu/simon-cox 

SDI Unit: http://sdi.jrc.ec.europa.eu/ 
IES Institute: http://ies.jrc.ec.europa.eu/
JRC: http://www.jrc.ec.europa.eu/
--------------------------------------------------------

-----Original Message-----
From: xmlschema-dev-request@w... [mailto:xmlschema-dev-request@w...] On
Behalf Of Andrew Welch
Sent: Wednesday, 2 September 2009 16:46
To: noah_mendelsohn@u...
Cc: Tsao, Scott; G. Ken Holman; Henry S. Thompson; xmlschema-dev@w...;
ekimber
Subject: Re: Best Practices for Establishing Namespace Name

2009/9/2  <noah_mendelsohn@u...>:
> Hi, Scott.  Further endorsing the advice that Henry and Eliot have 
> given you, I suggest you might be interested in the TAG's finding that 
> specifically encourages you to provide useful information that can be 
> retrieved using the namespace URI.  See [1].
>
> Noah
>
> [1] http://www.w3.org/2001/tag/doc/nsDocuments/


...but avoid using dates, for example:

http://www.w3.org/1999/XSL/Transform
http://www.w3.org/2001/XMLSchema

would have been much better as:

http://www.w3.org/XSLT
http://www.w3.org/XMLSchema

....then you don't have to reassure newbies that they really are using
modern technologies (2.0 and 1.1), despite what they may think from the
namespace.

I would say the main thing is to choose a namespace that wont need to
change, so don't use dates, versions, "beta", codenames etc.  Also the
namespace is often its branding, so using product names might be great until
marketing change their minds and call the product something else... if the
xml is visible to the customer they may ask for the namespace to change too.

So as an example, if the company is called "foo" and the product is
"foobar", you would probably choose "http://foo.com/foobar", which is most
likely going to be ok, but I'm beginning to think that "http://foo.com/ns"
is the better choice.





--
Andrew Welch
http://andrewjwelch.com
Kernow: http://kernowforsaxon.sf.net/