Presentation of XML Namespaces

An XML Namespace is the tool which can be used to identify and outline xml elements, this makes it much better to perform around various systems by having a global standard such as the “namespace”.

As much as xml is extensible, ie it could be expanded and employed in a wide range of methods, if you don't follow a set standard for the namespace you can not really implement xml without experiencing conflicts.

This is pretty self evident as you can not use various kinds of data using completely different namespaces, the format needs to be consistent in order that it can be understood and viewed through different programs and systems.

XML requirements are supervised by the W3C who usually write and control the xml specifications, additionally they specify a standard for the namespace by means of their namespace recommendations.

These types of guidelines incorporate things such as Name conflicts in XML can easily be prevented with a name prefix. So for example you have an xml file with a variety of tables, you may prevent conflicts issues by having unique prefixes for each and every table, like a a:table or b:table etc.

When making use of prefixes in XML, a so-called namespace for the prefix must be described, the namespace is defined by the xmlns attribute in the start tag of an element. The namespace declaration has the following syntax. xmlns:prefix="URI".

When a namespace is defined for an element, every child elements with the exact same prefix are linked to the same namespace. Namespaces may be declared in the elements where they are utilized or in the XML root element.

As said previously, xml is extensible, there is no semantic meaning and you may produce your own tags, having said that clearly unless you follow a recognized format or process then clashes can arise, and again having a prefix can remedy this.

The prefix unambiguously identifies the type of rating on this document. Nevertheless prefixes by themselves take care of practically nothing simply because anybody can create prefixes. Therefore, different people can create mismatched prefixes and we're back to step one: we've move the risk of conflicts from element names to prefixes. To prevent conflicts in prefixes, the prefixes must be declared.

This assertion usually follows the format of a URI, or Uniform Resource Identifier with a prefix as shown above, this is due to URI are in fact wholly unique whereas names or tags are not.

The prefix moreover, the full URI definition are certainly not interchangeable as URI’s can contain characters that are illegal in an XML namespace. It is also against the law to utilize the 3 letters XML in any event arrangement for a namespace prefix for the reason that are set aside.

Let's hope it's gone someway to provide the very idea of namespaces however I passionately advocate even more reading about this matter, a great deal of info is available on XML for many who wish to find out. For the definitive guide, visit W3.org or the W3C website.

Or for more complex readers, you'll find namespace tutorials with actual namespace examples here, http://www.liquid-technologies.com/Tutorials.aspx