System and method for schema evolution in an E-commerce network

A method of using a second tag in place of a first tag in an XML document, the method including:

• receiving the XML document that includes the second tag defined in a second schema and a reference to the second schema stored on a second server;
• processing the second schema, which defines the second tag including
• a reference to the first tag defined in a first schema stored on a first server, wherein the reference identifies the first tag as being extended;
• and
• an additional element from markup language that is not included in the first schema as part of the definition of the first tag;
• and
• processing the second tag as a polymorphic encoding of data in the XML document, such that the first and second schemas respectively allow use of the first or second tag in the electronic document;
• whereby applications and document types that use the first or second tag can evolve separately.

A method of an online service processing an XML document that extends a first XML document, the method including:

• receiving the XML document that includes a second tag,
• wherein the XML document references a second schema on a second server that defines the second tag, including
• a reference to a first tag in a first schema on a first server, wherein the reference identifies the first tag as being extended;
• and
• an additional element from XML markup language, not included in the first tag;
• and
• wherein the first tag is defined in the first schema to include a plurality of elements from the XML markup language;
• further including processing the XML document containing the second tag, in case the online service is configured to process data according to the second schema, by processing the additional element of the second tag and, in case the online service is adapted to process data according to the first schema but not the second schema, by not processing the additional element of the second tag but still processing the plurality of elements of the first tag;
• wherein the second tag polymorphically encodes data within the XML document;
• whereby the first and second schemas respectively allow use of the first or second tag and whereby applications and document types that use the first or second tag can evolve separately.