W3C XML Schema

Birthplace:

W3C

Age:

7 months

Parents:

SOX, XDR, DDML, …

Type:

Grammar

Formalism:

ad hoc. A formalism is being developed.

Syntax:

XML instance

  • Explicit type hierarchy with subclassing by restriction or extension

  • Provides a detailed PSVI to downstream applications

  • Includes a rich library of built-in datatypes

  • Extension and restriction of built-in datatypes with facets

  • Does not support co-constraints

  • Schema instance namespaced attributes are always allowed

  • Requires instance modification (xsi:type attribute) to enforce some constraints