Guide to XML Namespaces

An XML namespace is a great way to ensure consistency in your XML file and to avoid possible conflicts with badly named elements or attributes.

An XML Namespace serves as a tool that can be used to spot and outline XML elements, this will make it quicker to function across diverse systems by using a global specification such as the “namespace”.

XML Namespaces How To
XML Namespaces How To

As much as XML is extensible, ie., it could be extended and utilized in a wide range of styles, unless you follow a set standard for the namespace you are unable to really utilize XML without enduring conflicts.

This is pretty self-evident as you can not make use of different types of data working with different namespaces, the format should be continual in order that it can be comprehended and construed through different programs and systems.

XML requirements are maintained by the W3C who usually write and control the XML benchmarks. Furthermore, they specify a specification for the namespace through their namespace recommendations.

These recommendations consist of things like Name conflicts in XML could be easily prevented having a name prefix. So, for instance, you have an XML file with a variety of tables, you can prevent conflicts issues with unique prefixes for every table, like a “a:table” or “b:table” etc.

When making use of prefixes in XML, a so-called namespace for your prefix should be described, the namespace is defined by the “xmlns” attribute in the start tag of an element. The namespace declaration has got the following syntax:


Whenever a namespace is defined for an element, every child element with the same prefix is linked to the same namespace. Namespaces may be declared in the elements in which they are used or even in the XML root element.

As mentioned previously, XML is extensible, there is absolutely no semantic meaning and you can produce your own tags, unless you follow an unaccepted format or procedure. Then, issues can occur and, again, using a prefix can remedy this.

The prefix unambiguously specifies any type of rating in this document. However, prefixes on their own solve nothing at all simply because anyone can create prefixes. For that reason, different people may make mismatched prefixes and we are back to step one: we now have moved the potential for conflicts from element names to prefixes. In order to avoid conflicts in prefixes, the prefixes need to be declared.

This declaration normally follows the format of a URI, or Uniform Resource Identifier, which has a prefix as presented above, it is because URI is actually wholly unique whereas names or tags are not.

The prefix furthermore, the entire URI definition aren’t interchangeable as URI’s can contain characters that are illegal in an XML namespace. It is additionally illegal to utilize the 3 letters XML regardless of arrangement for a namespace prefix.

Or for more technical readers, you will find namespace tutorials with actual namespace examples here,

For the definitive guide, visit or the W3C website.

This was a guest post by Michael Dupre.