Walking through a schema XML Schemas are built using a set of predefined XML elements and attributes, which define the structure and content model of a document.

We can define the vocabulary (what elements and attributes an XML document can use) using either a document type definition (DTD) or the XML Schema language.

We’ll modify the schema to include the supported appointment types and add a customization that causes the schema compiler to map the elements of ApptType to a Java typesafe enum class.

Microsoft announced the addition of the Microsoft Office Visio 2003 XML Reference Schema to its open and royalty-free documentation and license program that was initially unveiled in November 2003.