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Difference between revisions of "Attribute"
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==Examples== | ==Examples== | ||
| − | The | + | The person Bob Smith might be represented as a [[Node]] in the [[Context]] of his employer, the Port Control Authority. This [[Node]] might have the following types of [[Attribute]]s (and associated values) in this [[Context]]: |
* email-address = bob@portcontrol.gov | * email-address = bob@portcontrol.gov | ||
* phone number = {617-555-1234, 617-333-4321} <-- multi-valued attribute example | * phone number = {617-555-1234, 617-333-4321} <-- multi-valued attribute example | ||
| Line 35: | Line 35: | ||
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. | 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 | + | This same Bob Smith might also be represented as a [[Node]] in a "customer-to-Clothes-R-Us" [[Context]] (this customer's relationship with the Clothes-R-Us merchant. In this [[Context]] Bob has these [[Attribute]]s: |
* platinumCustomer = True | * platinumCustomer = True | ||
* preferredColor = "blue" | * preferredColor = "blue" | ||
Revision as of 13:18, 22 April 2008
{{#eclipseproject:technology.higgins}}
Contents
Version
This pages describes the concept of Attribute used in Higgins Global Graph 1.1
Definition
- Defines a property of an Node or a Context.
- Has a type (URI)
- Has one or more values all of which MUST be unique
- Has either simple or complex value(s)
- Simple values:
- Are literal values (e.g. "green") based on a "base" XML Schema type URI (e.g. string)
- The allowed value(s) are defined by a Data Range (URI)
- Complex values are Nodes
Implementation note: Complex values are likely stored internally as NodeId Data Range URIs that are dereferenced to produce Node instances.
Kinds of Attributes Defined in HOWL
Examples
The person Bob Smith might be represented as a Node in the Context of his employer, the Port Control Authority. This Node 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} <-- multi-valued attribute example
- 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 Bob Smith might also be represented as a Node 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 if the values are the same. For example a very odd father might name each of his three kids "frank". Thus the father Node 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"