The possibility to share content easily among e-business partners constitutes one of the Web's potentials. Especially XML facilitates interoperability between different e-business partners by providing a standard representation of content. But the support of reacting automatically to changes in related documents is still weak. Active XML Schemas extend XML Schemas in that respect. Active XML Schemas employ concepts from active database systems, from conceptual modeling of business rules, and from event-based systems to provide for automatic and asynchronous management of distributed web content. Different to previous approaches of employing the event-condition-action (ECA) paradigm in a web-based setting, active XML Schemas integrate passive and active behavior smoothly into document schemas in an object-oriented way, treat events as "first class elements" that can be stored and queried just as other document data, and provide for logical events that are defined upon querying past and scheduled events.
