XML: A Managers Guide (2nd Edition) (Addison-Wesley Information Technology Series)

Shared context is a formal description of the rules metadata must follow. If people had a standard way to express shared context, they could quickly reach agreement on how to conduct an information exchange. In a document-centric architecture, shared context applies to a particular type of document and serves as a contract between the document sender and the document recipient. The document sender agrees that the document conforms to the shared context. The document recipient agrees to interpret the document according to the shared context.

In the case of business-to-business commerce, two companies may agree to a shared context for "Order" documents. Part of this shared context might be that (a) an "Order" can have one or more "Line Items"; (b) each "Line Item" has an "SKU," a "Unit Price," and a "Quantity"; and (c) "Unit Price" is a number with two decimal places and represents U.S. dollars. This approach could help address many of the information exchange problems just discussed.

• To solve the problem of organizing data on the Web ”such as home search results ”one could develop a universal shared context for tabular data.

• One could help solve the database access problem by defining a universal shared context that describes how a database organizes data and the relationship of the data to common business concepts.

• Business-to-consumer electronic commerce could become much more efficient through shared contexts for catalog structure, orders, and receipts.

• Business-to-business commerce could become much more efficient through frameworks that enable businesses to describe shared contexts for purchase orders, invoices, and business process descriptions.

• The knowledge-sharing problem could become easier by enabling collaborators to defining shared contexts for each class of problem they want to solve jointly ”for example, special contexts for product development, special contexts for developing medicines from gene sequences, and special contexts for naval task force combat information.

Shared context does not provide complete spontaneity, but it comes close. At least one party must develop the shared context. However, the party can then make the shared context available on the Internet and anyone else can participate in the information exchange it governs. The shared context developer doesn't even have to be a party to these exchanges. One could imagine an organization dedicated to developing such shared contexts as a community service or commercial venture. It might never use the shared context itself; it would simply provide the seed for other parties to begin spontaneous information exchange. The beauty of this approach is that the connectivity of the Internet becomes part of the solution. The developer of a shared context can simply post it to the Internet, where it becomes available to anyone who is interested.