Difference between revisions of "Attribute"

Revision as of 14:43, 3 February 2008

Introduction

This page describes the Higgins concept of Attribute.

Definition

• Defines a property of an I-Node or a Context.
• Has a URI-valued type that:
  • Identifies the Attribute instances with a given I-Node or Context
  • Identifies the Attribute's Attribute Model
• Has one or more values all of which MUST be unique
• The types of the values of an Attribute may be:
  • XML-Schema-based literal datatypes (a specific sub-set of the XML Schema literal types)
  • Sub-types of the XML-Schema-based literal datatypes
  • Complex (structured) datatypes
• The set of values of a single Attribute may be any combination of the value types

Examples

The physical person Bob Smith might be represented as an Entity in the Context of his employer, the Port Control Authority. This Entity might have the following types of Attributes (and associated values) in this context:

• email-address = bob@portcontrol.gov
• phone number = {617-555-1234, 617-333-4321}
• passport information = ...etc.
• fingerprint data = ...etc.
• surname = "Smith"

The surname Attribute in the example above might have a type of http://openschemas.org/2006/person/surname. The schema associated with the containing Context provides metadata about this URI.

This same physical person Bob Smith might also be represented as a Entity in a "customer-to-Clothes-R-Us" Context (this customer's relationship with the Clothes-R-Us merchant. In this Context Bob has these Attributes:

• platinumCustomer = True
• preferredColor = "blue"

HOWL

Open Issues

• At present an attribute cannot have N>1 values where the values are the same. For example a very odd father might name each of his three kids "frank". Thus the father Entity cannot have an attribute "names-of-children" whose values are "frank, frank, frank".
• We need to be able to describe the reality that "real world" context providers must restrict attributes to be "closed"

Kinds of Attributes

• Context Relation
• Context Correlation
• I-Node Relation
• I-Node Correlation

See Also

• Concepts
• Higgins Global Graph

Links

• Higgins Home