Exploring XML

Introduction

XML (Extensible Markup Language) is a platform-independent universal language that enables you to create documents in which data is stored independently of the format so you can use the data more seamlessly in other forms. XML is a markup language just like HTML. You mark up a document to define the structure, meaning, and visual appearance of the information in the document.

When you mark up a document, using XML or HTML, you use codes called tags that define the appearance or structure of the document. In HTML, the tags define the appearance and location of your data, while in XML, the tags define the structure and meaning of your data. For a HTML document, the tags determine where titles, text, and information goes in a document. For a XML document, the tags defines the kind of data, which makes it possible to reuse or exchange data. The

You cannot use HMTL in place of XML. However, you can wrap your XML data in HTML tags and display it in a Web page. HTML is limited to a predefined set of tags, while XML allows you to create tags that describe your data and its structure. This makes XML an extensible markup language.

In order to share XML data among programs and operating systems, it needs to be well-formed, which means it conforms to a standard set of XML rules. In addition to well-formed data, XML also uses schemas and transforms. A schema is an XML file (.xsd extension instead of the typical .xml) with a set of rules that defines the elements and content used in an XML document. XML schemas are created by developers who understand XML. The schema is used to validate the data in an XML document and help prevent corrupted data. After you validate an XML data file with a schema, you can apply a transform that allows you to reuse the data in different forms, such as a document or worksheet, or exchange the data with a data system, such as a database. The XML data file, schema, and transform make up the components of a XML system.

Microsoft Office XML

XML is supported in Microsoft Office 2007 through PowerPoint, Word, and Excel. Each of these Office programs uses XML (New!) as the default file format. XML allows you to work with the Office interface and create XML documents, without ever knowing the XML language. In Word and Excel, you can use the Developer tab to work with XML structure, schema, and documents. In Access and Excel, you can import and export XML data. Office programs can work with schemas, transforms, and data from other suppliers as long as the XML is well-formed.

XML Benefits

The XML format significantly reduces file sizes, provides enhanced file recovery, and allows for increased compatibility, confidentially, sharing, reuse, and transportability. The XML format uses ZIP and other compression methods to reduce the file size by as much as 75%. Since XML separates the data from the structure and meaning, it's easier for Office program to recover data or remove sensitive information. In fact, you can even open a damaged file in Microsoft Notepad to recover some of the information. The XML format is also royalty free, which makes it more available.