| Microsoft XML Core Services (MSXML) 5.0 for Microsoft Office - XML Developer's Guide |  |
| Microsoft XML Core Services (MSXML) 5.0 for Microsoft Office - XML Developer's Guide | |
The appeal of XML lies in the ability to invent tags that convey meaningful information that can be processed by applications and read by users. Namespaces allow you to associate a vocabulary (or namespace) with an element or attribute name.
The following XML represents information about a book.
<BOOK> <TITLE>XML Developer's Guide</TITLE> <PRICE currency="US Dollar">44.95</PRICE> </BOOK>
The following XML represents information about an author.
<AUTHOR> <TITLE>Ms</TITLE> <NAME>Ambercrombie Kim</NAME> </AUTHOR>
Although the user can distinguish between the different interpretations of the <TITLE> element, a computer program, such as an XML parser, cannot differentiate between the two meanings. Without additional information, the parser cannot determine that the first <TITLE> element is intended to refer to a string representing the title of the book, and that the second refers to an enumeration representing the title of the author ("Mr. ", "Ms. " , "Mrs. " , and so on).
The following examples shows TITLE associated with BookInfo and AuthorInfo namespaces.
<BookInfo:TITLE xmlns:BookInfo="books-namespace-URI">XML Developer's Guide</BookInfo:TITLE> <AuthorInfo:TITLE xmlns:AuthorInfo="authors-namespace-URI">Ms.</AuthorInfo:TITLE>
The W3C Namespaces in XML recommendation provides the xmlns attribute to uniquely define a namespace for an XML document to use.
The following examples show how to declare a namespace with the xmlns attribute.
xmlns=http://www.example.microsoft.com/books.dtd xmlns="urn:schemas-microsoft-com:xml-data