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| − | {{#eclipseproject:technology.higgins}}
| + | #REDIRECT [[Entity]] |
| − | [[Image:Higgins_logo_76Wx100H.jpg|right]]
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| − | == Introduction ==
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| − | This page describes the Higgins concept of [[Node]].
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| − | It is similar to the [http://wiki.idcommons.net/index.php/Digital_Subject Identity Gang Lexicon's definition of Digital Subject]. The term was changed to eliminate any possible confusion with the term subject (or data subject) in international privacy law.
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| − | A Higgins [[Node]] is a representation of an [[Entity]] ''within a given context.'' [[Node]]s and [[Entity | Entities]] are not the same concept. The distinction is subtle but critical. In Higgins the same [[Entity]] is usually represented by multiple [[Node]]s in different [[Context]]s.
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| − | == Definition ==
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| − | * A digital representation of an [[Entity]]
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| − | * A [[Node]] has zero or more [[Attribute]]s
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| − | == Details ==
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| − | * Although not strictly required, almost all [[Node]]s have a single [[NodeId]] [[Attribute]] in addition to whatever other kinds of [[Attribute]]s they may have. This [[NodeId]] [[Attribute]] has a value of type [[NodeId Data Range]] and uniquely identifies the [[Node]] within its containing [[Context]].
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| − | * Some of the [[Attribute]]s of an [[Node]] may be references to other [[Node]]s in the same or different [[Context]]s. These are called [[Node Relation]]s. For example, an [[Node]] representing the [[Entity]] Bob may have a "knows" [[Node Relation]] [[Attribute]] pointing to an [[Node]] representing Bob's friend Alice.
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| − | * A single person (thing or concept) may be represented as one (or more) [[Node]]s in one [[Context]] and (an)other [[Node]]s in other [[Context]]s. By linking or "federating" these disparate [[Node]]s one can gain a more unified view of a given person. [[Context]]s representing different systems, organizations and entire enterprises with widely varying storage and trust models are handled using this [[Node]] linking approach. For example the person "Bob Smith" could be represented as two [[Node]]s; the first having "bsmith" as an [[NodeId]] and the second having "bob" as a [[NodeId]]. These two [[Node]]s may be in the same or in different [[Context]]s. To express that the "bsmith" is the same person as "bob" an [[Node Correlation]] [[Attribute]] would be added to "bsmith" whose value points to "bob".
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| − | * [[Context]]s can be nested (e.g. enterprises have sub-organizations, and there are systems within an enterprise/org, etc.) or related through other means (employment/HR system vs. customer system where same person is a customer and an employee). Thus linking the [[Node]]s relevant to those contexts provides an a broader view of a [[Node]].
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| − | * The information contained in one [[Node]] is not necessarily a pure subset of the union of all of the information contained in all of the linked [[Node]]s representing a person taken together. There is no consistency constraint imposed between the [[Node]]s of an person. For example, a person could be represented such that their name was Joe in one [[Node]] in one [[Context]] and JoAnn in another [[Node]] in another [[Context]].
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| − | == Node Subclasses ==
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| − | Each [[Context]] has an associated ontology/schema. This schema must import and build on the terms in HOWL. Within this ontology the [[Context]] can define its own [[Node]] subclasses and [[Attribute]] types. When defining a [[Node]] subclass, the class definition can place restrictions on the cardinality of [[Attribute]] types also defined in the ontology. A given [[Node]] subclass:
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| − | * MAY define the minimum cardinality of an [[Attribute]], that is, the minimum number of values allowed (e.g. >=3 values)
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| − | ** MAY define the maximum cardinality of an [[Attribute]], that is, the minimum number of values allowed (e.g. <=100 values)
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| − | == HOWL ==
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| − | <pre>
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| − | </pre>
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| − | == See Also ==
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| − | * [[NodeId]]
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| − | * [[Concepts]]
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| − | [[Category:Higgins Concepts]]
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