The W3C documents current at this writing are available online: the XML Schema home page and the XML Schema specification, consisting of XML Schema Part 0: Primer, XML Schema Part 1: Structures, and XML Schema Part 2: Datatypes.A useful Java package is Apache XMLBeans, which provides methods to marshal and unmarshal XML to/from Java objects and also a most useful verification tool ( if it is a child element of the schema element (rather than a child of a child, or a child of a child of a child, etc). An XML element can identify its schema(s) in the attribute's value is a single URI for the schema for elements and attributes with no namespace. The type is defined either as part of the element definition, or elsewhere as a named type (with the Although the same XML Schema constructs are used to define element and attribute types, those types are interpreted in different ways.Each type can also be considered as a possibly infinite set of strings representing the values of the type (the type's lexical space).Ordinarily there is no need to keep this distinction in mind.
Such definitions may contain these attributes: indicates the default value of an attribute or element; the default value is assumed for an attribute that does not appear, or for an element with empty content.
The XSD standard has evolved over a number of years, and is controlled by the W3C.
It is extremely comprehensive, and as a result has become rather complex.
In example (a) above, is defined at the top level, then the XML file may contain an instance of the element as its sole contents; otherwise, the XML file may contain an instance of the element as part of another element. In addition, a new complex type may be derived by from an existing complex-complex type by a restriction that reduces the child elements allowed or the type of a child element.
In either case, the restriction of a complex type can reduce the scope of one or more attributes of the type.
There are several ways one schema can incorporate types, elements, attributes, and groups defined in another schema (besides simply copying the text, which always works).