"Mike Morse" <mike.morse@micromo.com> wrote in message
news:%23XQ3dHYdEHA.720@TK2MSFTNGP11.phx.gbl...
> What see sample that show xs:element where the xs namespace =
> http://www.w3.org/2001/XMLSchema
>
> However, I see another example with xsi: where xsi =
> http://www.w3.org/2001/XMLSchema-instance
>
> What's the difference here? Are there right and wrong namespaces? Is
there
> a global list of the ones to use? Does the namespace even need to point
at
> http://www.w3.org.....? Or is this just the accepted way?
>
> Very appreciative,
>
> Mike Morse
>
>

"Dino Chiesa [Microsoft]" <dinoch@online.microsoft.com> wrote in message
news:OQXi8QZdEHA.1692@tk2msftngp13.phx.gbl...
> They are different namespaces that refer to different things.
>
> for more on XML Namespaces, See
> http://www.w3.org/TR/REC-xml-names/
>
http://msdn.microsoft.com/library/en-us/xmlsdk/html/xmconUsingNamespacesinSchemas.asp
> http://msdn.microsoft.com/library/en-us/dnxml/html/xml_namespaces.asp
> http://www.jclark.com/xml/xmlns.htm
>
> The examples you cited do not "point to" www.w3.org. In fact, XML
> Namespaces in general are supposed to be URI's, and are not necessarily
> URL's.
> The page I referenced above points to RFC2396 which clarifies the
> distinction between URI's and URL's.
> http://www.faqs.org/rfcs/rfc2396.html
>
> In a nutshell, a URI is an Identifier, whereas a URL is special case of
URI
> that is also a Locator. My name "Dino Chiesa" is an Identifier, but is
> not a Locator. (but, my name is NOT a URI, because it does not conform to
> RFC2396). http://www.w3.org is both an identifier and a Locator.
(both
> a URI and URL). The string "urn:ThisIsMyNamespace" is a URI but not a
> URL, as it provides no location information.
>
> It just so happens that the URI's used for XMLSchema and
XMLSchema-instance
> (and many other XML namespaces) also act as URLs. It need not be so.
> Designers often use http:// prefixes in XML namespaces, for a couple
> reasons.
> 1. it makes the doc easy to find. If I want to learn about XML Schema,
I
> can go to http://www.w3.org/2001/XMLSchema
> 2. HTTP URLs are universal and hierarchical. For example, a namespace
> like http://www.w3.org/2001/XMLSchema indicates that W3C owns it (or
> published it), that it was finalized in 2001, etc. A namespace like
> http://www.mycompanyname.com/Blah/Foo would indicate that MyCompanyName
> specified it. So it's easy to discriminate namespaces this way.
>
> But, on the other hand, dual use URIs tend to confuse people as to the
> purpose and nature of XML Namespaces.
>
> Microsoft has tried, in the namespaces it publishes, to use URNs as
opposed
> to URLs. I think.
> For example, the Office Search Pane can interpret documents that conform
to
> the namespace "urn:Microsoft.Search.Response" . The namespace used in
> ADO.NET DataSets is urn:schemas-microsoft-com:xml-msdata .
>
> These are URI's (and URN's) but not URLs.
>
> -D
>
>
> "Mike Morse" <mike.morse@micromo.com> wrote in message
> news:%23XQ3dHYdEHA.720@TK2MSFTNGP11.phx.gbl...
> > What see sample that show xs:element where the xs namespace =
> > http://www.w3.org/2001/XMLSchema
> >
> > However, I see another example with xsi: where xsi =
> > http://www.w3.org/2001/XMLSchema-instance
> >
> > What's the difference here? Are there right and wrong namespaces? Is
> there
> > a global list of the ones to use? Does the namespace even need to point
> at
> > http://www.w3.org.....? Or is this just the accepted way?
> >
> > Very appreciative,
> >
> > Mike Morse
> >
> >
>
>