Explanation: To define the legal building blocks of an XML document, the XML Schema is used. This includes the elements and attributes that can appear in a document, the number of and the order of the child elements, the data types for elements and attributes, and the default and fixed values for the elements and attributes.

XSD Data Types XSD String XSD Date/Time XSD Numeric XSD Misc XSD Reference Web Services XML Services XML WSDL XML SOAP XML RDF XML RSS ... Test your XML skills at W3Schools! Start the XML Quiz! Kickstart your career. Get certified by completing the course. Get certified w 3 s c h o o l s C E R T I F I E D. 2 0 2 2

Note: To enable character data to appear between the child-elements of "letter", the mixed attribute must be set to "true". The <xs:sequence> tag means that the elements defined (name, orderid and shipdate) must appear in that order inside a "letter" element.

Element Description; id: Identifies the entry using a universally unique and permanent URI.Suggestions on how to make a good id can be found here.Two entries in a feed can have the same value for id if they represent the same entry at different points in time.