[June 19, 2000] A communiqué from John McClure (Principal Engineer, Hypergrove Engineering) reports on the release of documents related to XML-based designs for real estate information; technical feedback on the design approach and implementation is being sought. "The Data Consortium is an open-membership group of more than 50 companies and associations whose goal is an open-source standard namespace for the commercial real estate industry. To that end, a preliminary, annotated DTD has been posted, to be followed by an explanatory guide, and an active glossary and RDFS dictionary. The Data Consortium Namespace (DCN) defines just 13 key elements, whose instances are cross-related in a manner anticipating coordination of XML streams with relational database CRUD functions. These 13 elements are generic: Account, Actor, Document, Entry, Event, Item, Location, Property, Right, Role, Service, System, and Transaction. These 13 elements are specific: by referencing XML Schema and RDF Schema definitions, four levels of categorization, i.e., instance naming, can be simultaneously achieved. In two ways, the DCN extends notions introduced by the Resource Description Framework (RDF). The DCN defines a <list> element that contains a collection of relationships to other resources while RDF's <bag> elements relates a resource to a collection of attribute values. Second, the DCN positions its <Location> element as a building block for RDF's grammatical elements (Sentence, Subject, Predicate). The DCN also defines four property-elements whose names are abstract XML Schema datatypes. Similar to the key elements (above), every instance of a property-element has a naming mechanism coordinated with both an XML Schema and an RDF Schema. Numeric properties may be a numeric range, while all properties may have a keyword value that is a qualified name. Further, the vCard, Dublin Core, MathML, XQL, XLink, and XPointer each have a place within the DCN. We welcome your review of the design and implementation."
References:
Data Consortium Namespace DTD. "DCN 1.0 is a specification for the Data Consortium Namespace. This document defines Extensible Markup Language (XML) elements and attributes for expressing information related to commercial properties listed for sale, lease, or assignment. DCN 1.0 includes a set of terms that are referenced by elements in document instances." Also in .DOC (Word) format. [cache]
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