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Data Range


This page describes the concept of an Data Range.


  • The datatype and [optionally] constraints on the value of an Attribute
  • An Data Range MUST have a base XML Schema type (e.g. String)
  • An Data Range MAY include a set of constraint "facets" on its value(s). The names and semantics of these facets are taken from XML Schema. They include:
    • Value must be one of {"red", "green", "blue"}
    • Syntax constraints (e.g. regular expression)
    • ranges (e.g. less than 5, more than 100)

<to be completed>


  • An Attribute might have a value whose Data Range was defined in the Contexts schema as "telephone number". This telephone number Data Range might have a base type of (XML Schema) string, but might also have an XML Schema pattern facet that constrained its syntax to be value in North America for auto-dialing (e.g. it is of the form (NNN)-NNN-NNNN)

Predefined Data Rangess

The following are predefined in HOWL:

  1. ContextIdDatatype
  2. NodeIdDatatype
  3. NodeRelationDatatype

See Also


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