XML schema describes the structure of the XML document.
n XML schema is a XML-based alternative to DTD.
n XML schema support name space.
n XML schema defines the elements, the number of child elements, the order of child elements, the attribute of the element, and data type.
n XML Schema has a lot of built-in data types including xs:string, xs:decimal, xs:integer, xs:boolean, xs:date,xs:time. The building blocks of DTD include elements, attributes, entities, PCDATA, and CDATA.
n XML schema supports inheritance.
XPath is a query language to select nodes from XML documents. It is based on a tree representation of the XML document.