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7. XPath enumerations
[> 8.][< 6.0][^^^]
7.0 Exhaustive enumeration of information items
[> 8.][< 7.][^^][^^^]
Constraint expressions (as used in the UBL schemas) reveal only the parent/child relationship between information items
[[1] - one cannot readily tell the impact of the additional number of possible descendents being added to a given element when choosing to include a particular child for that element
]
The complete ancestry of possible information items is only available through an analysis of the parent/child constraints at every possible level of the document tree
[[1] - the UBL TC has performed the analysis and summarized all of the elements and attributes in all contexts of all document types
]
The information is made available in four forms of what the committee has termed "XPath files"
[[1] - a normative description in XML of all possible ancestral and descendent paths of an XML instance
[[2] - this description can be processed for analytical purposes
][1] - a simple text report of the absolute minimum set mandatory information items required to satisfy the document model
 [1] - a simple text report of all possible information items defined by the document model use of elements
 [1] - an exhaustive sample XML instance that can be processed by non-validating applications
]
Complete suite of XPath information created from the document models
[[1] - could be based on the regular nature of the W3C Schema XSD expressions
 [1] - could be based on the model information of parent/child relationships
 [1] - drawback of being very large files
[[2] - e.g. there are over 800,000 information items (not including recursion) in the UBL Order model
]]
Can also create XPath files from instances
[[1] - useful when working with a limited number of information items instead of an exhaustive enumeration
 [1] - drawback of being fragile
[[2] - changing anything in the instance renumbers all reference numbers from that point to the end of the document
][1] - Crane has a number of XPath-related resources available in the "Free resources" section of the web site linked from the right-hand marginalia of:
[[2] - [http://www.CraneSoftwrights.com/links/trn-20090212.htm]
]]
UBL XPath files are used in the creation of a number of related resources
[[1] - e.g. stylesheet development
]

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+//ISBN 1-894049::CSL::Presentation::UBL//DOCUMENT Practical Universal Business Language Deployment 2009-02-12 13:50UTC//EN
Practical Universal Business Language Deployment
Third Edition - 2009-02-12
ISBN 978-1-894049-23-8
Copyright © Crane Softwrights Ltd.