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Enhancing Metadata of RDF Collections

IP.com Disclosure Number: IPCOM000222601D
Publication Date: 2012-Oct-18
Document File: 4 page(s) / 38K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a way to describe some missing metadata for Resource Description Framework (RDF) container types and List type properties. In particular, the invention allows the type, cardinality, and uniqueness restrictions to be specified for such properties in a way that applies to their members, and in a way that is consistent with RDF and can easily be leveraged by RDF modeling tools.

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Enhancing Metadata of RDF Collections

In Resource Description Framework (RDF), there are a few ways of specifying collections. The most common way is to specify an unordered collection with no duplicates, and this can be specified with a regular property definition. For example, the following triples defines that a Teacher (the domain of the property) teaches (the property) a number of courses (the range of the property). Notice that properties with no cardinality restrictions are assumed to have 0...* cardinality.

An example of the usage of such property in an RDF graph is as follows:

Min/Max cardinality of such properties can be restricted in the context of some class. For example, the following restricts a Teacher to teach at least one course (by making class Teacher subclass from a restriction class that restricts the minimum cardinality of property "teaches" to 1).

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However, RDF also provides ways to define other types of collections. For example, it provides a container vocabulary that consists of three predefined types:


 A Bag represents a container that may have duplicate members whose order is not significant


 A Seq represents a container that may have duplicate members whose order is significant


 An Alt represents a container of alternative members

An example of a property that represents such a container is as follows (notice that the range of the property is set to Bag):

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An example of the usage of such property in an RDF graph is as follows:

The other way RDF provides for defining collections is a List (i.e., a linked list), which is ordered and allows duplicate members. An example of a property that represents such a list is as follows (notice that the range of the property is set to List):

An example of the usage of such property in an RDF graph is as follows:

Furthermore, there are a number of problems with the last two ways of defining collections (i.e., container types and List):


 There is no way to specify the type of the collection's members (either through the range of the property or the type restrictions)


 There is no way to specify a cardinality for the collections members (through cardinality restrictions)


 There is no way to specify the uniqueness of the collections

Note: The reason that you cannot use property restrictions...