What is the significance of namespace in xml

There are two further substantive changes:. There are several editorial changes, including a number of terminology changes and additions intended to produce greater consistency. The contributions of Charles Frankston of Microsoft were particularly valuable. Namespaces in XML 1.

Abstract XML namespaces provide a simple method for qualifying element and attribute names used in Extensible Markup Language documents by associating them with namespaces identified by IRI references.

Status of this Document This section describes the status of this document at the time of its publication. Table of Contents 1 Motivation and Summary 1. Namespace constraint: Prefix Declared The namespace prefix, unless it is xml or xmlns , MUST have been declared in a namespace declaration attribute in either the start-tag of the element where the prefix is used or in an ancestor element i.

In addition, a namespace-well-formed document may also be namespace-valid. The original character is replaced by the resulting character sequence.

Bradner, ed. Moats, ed. Berners-Lee, R. Fielding, and L. Masinter, eds. Hinden, B. Carpenter, and L. Faltstrom, P. Hoffman, and A. Costello, eds. Yergeau, ed. XML 1. Duerst and M. Suignard eds. March 2, October 26, Sperberg-McQueen, 6 September Requirements Namespaces in XML 1.

The following is an example of how to add a namespace definition for the item namespace to the xsl-stylesheet-prolog entry:. In both cases, the namespace declaration must be included in the XML element's start tag. Adding the definition to the XMLADI document element start tag is easiest to do because it automatically defines the namespace for the entire document.

Therefore, any ADI items in the document whose names are prefixed with this namespace ID do not have to have the namespace definition added to their own element start tag. This method does not suffer any of the drawbacks of defining the namespace by using the second method. The [xmladi-attribute-definitions] stanza has been added to the configuration file to allow customers to define namespaces globally for use within the XMLADI document.

With an explicit declaration, you define a shorthand, or prefix, to substitute for the full name of the namespace. You use this prefix to qualify elements belonging to that namespace. Explicit declarations are useful when a node contains elements from different namespaces. A default declaration declares a namespace to be used for all elements within its scope, and a prefix is not used.

First, we will create a root element employeeList element and an element personList element to summarize employee information for one individual. You might have thought about creating an employee ID element empID element in employeeXML document , department name element name element in sectionXML document and an employee name element name element in employeeXML document as child elements, but there's a problem with this method.

The problem is an "element name conflict. In merging these two XML documents, you will get a name element that has two separate meanings. While a human might be able to tell the difference between these two "name" elements and what they represent, computer systems cannot determine what these name elements are supposed to mean. The XML 1. The name element expressing employee name and the name element expressing department name conflict!

Perhaps some of you out there had the idea that element name conflicts can be avoided by applying the same type of alias used for RDB table merge explained above to an XML document. Utilizing this XML namespace allows us to avoid any element name conflicts. As a result, we can differentiate the "emp:name element" of the employeeList data XML document as an element representing employee name, and the "sec:name element" as an element representing department name. It might be easiest to think of one namespace as an aggregation of elements and attributes.

Write a namespace declaration according to the following description method, describing the element start tag:. As a test, let's take the previous employeeList XML document as an example, and provide a namespace declaration and an element belonging to the namespace.

In this example, we have declared the namespace prefix as "emp", and the namespace identifier URI as "urn:corp:emp". This means that element names and attribute names with the "emp" prefix including the employee element all belong to the urn:corp:emp namespace.

While the namespace declaration is described as a start tag attribute, this is different than a regular attribute. Any arbitrary text string can be used as a namespace prefix; since there is no special meaning, any text string will do. However, the URI must be universally unique. Since the URL is not actually accessed, it is not a problem if the file, etc. Understand that a URI represents nothing more than a logical namespace name.