Newbie Question About Namespaces

[Guest TJaze]

I have just started learning about schemas, and though I'm familiar with namespaces (being a programmer), I'm still a little unclear on how they are used in XML & schemas.Are these just a named reference used to identify a namespace, or do the URL addresses (often used in identifying namespaces), actually contain information that is referenced by the XML or schema file?

[Ingolme]

The URI of a namespace doesn't provide any information, it is just used as an identifier.The namespace just allows two elements of the same name, with different meanings, to be in the same document.

[boen_robot]

... or as you said it yourself, it's

just a named reference used to identify a namespace

Keep in mind that unlike languages like PHP, C and C#, namespaces in XML are not inhereted. Each URI is treated literaly, without any processing, and is therefore considered as the full namespace. That is, in

<a xmlns="http://example.com"><b/><c xmlns="/ns"/></a>

The <a/> and <b/> elements are in the "http://example.com" namespace, and the <c/> element is in the "/ns" namespace (NOT in the http://example.com/ns" namespace). In fact, to avoid such kind of confusion, recent editions of the XML namespaces specification deprecated relative URIs, and implementations are therefore encouraged to give warnings if you use such URIs.