The components of a basic XML system.
A typical XML system consists of three types of files:
XML data is your data, plus XML tags that describe the meaning and structure of your data.
XML schemas define rules for what can and cannot reside in your data files. For example, a schema could ensure that users can't enter words into a date field.
XML transforms enable the use of data in a variety of programs or files. For example, one transform could add sales data to a workbook, while another transform could insert the same data into a document.