iLingo - The Language of Insurance e-Business

Appendix A. XML Schemas and DTDs

iLingo uses the [W3C XML Schema Working Draft of 6-May-1999]. Although there have been later drafts, we have been reluctant to move forward until a new syntax stabilizes. In addition, we have been conservative in our use of XML Schema refinement/archetypes because they have been in flux.

With the recent drafts and the promise of a proposed recommendation, we will move iLingo forward in the near future. This will allow us to take advantage for more schema constructs and, thus, make iLingo more usable as a basis for XML in the insurance supply chain.

In many ways, the current iLingo represents three general uses of XML Schemas:

  1. An XML syntax for the schemas that allows us a great deal of flexibility.
  2. True data typing of "leaf nodes". That is, if something is a date, it is typed as a date.
  3. The current element types are really the manifestation of a more complex type system that we haven't modeled in the schemas and really represent the "leaf nodes" of this type system.

Given that we cannot guarantee that an XML schema processor exists at all points in the supply chain, we have provided XML DTDs that are generated from the XML schemas. These DTDs allow a document that conforms to the schema to syntactically parse and provide a certain level of validation. Although this validation cannot check all datatypes, it does provide the structural checking of content models and the verification of required attributes.