URIs

In the CSV file of a DCAP, URIs can be represented in three possible ways:

• as full URIs
• as full URIs enclosed in angle brackets
• as prefixed URIs (eg, dc:, wd:Q46914185)

The base URI of the DCAP can be depicted as a bare colon (:).

The Statement class performs some normalization of URI values (stripping out enclosing angle brackets) and checks whether URIs and prefixed URIs are basically well-formed. No attempt is made to cover all edge cases; the sanity checks are no substitute for careful modeling. There is also an attempt to catch inconsistencies in cases where one element depends on, or implies, another. For example:

• With a value type of URI, a constraint value (if provided) should be a URI or prefixed URI.
• A constraint type of UriStem implies that a constraint value is provided and is a URI or prefixed URI.

The following table shows various valid uses of URIs as constraint values.

shapeID	propertyID	value_type	constraint_value	constraint_type
:book	dct:subject		https://id.loc.gov/subjects	UriStem
:book	dct:subject		<https://id.loc.gov/subjects>	UriStem
:book	dct:subject		nalt:	UriStem
:book	dct:creator	URI	https://www.wikidata.org/wiki/Q46914185
:book	dct:creator	URI	wd:Q46914185

This is interpreted as:

DCAP
    Shape
        shapeID: :book
        start: True
        Statement
            propertyID: dct:subject
            constraint_value: https://id.loc.gov/subjects
            constraint_type: UriStem
        Statement
            propertyID: dct:subject
            constraint_value: https://id.loc.gov/subjects
            constraint_type: UriStem
        Statement
            propertyID: dct:subject
            constraint_value: nalt:
            constraint_type: UriStem
        Statement
            propertyID: dct:creator
            value_type: URI
            constraint_value: https://www.wikidata.org/wiki/Q46914185
        Statement
            propertyID: dct:creator
            value_type: URI
            constraint_value: wd:Q46914185

The following table illustrates a few simple inconsistencies that will be detected.

shapeID	propertyID	value_type	constraint_value	constraint_type
:book	dct:subject		some_string	UriStem
:book	dct:creator	URI	some_string
:book	dct:subject			UriStem

Note:

• The string ‘some_string’ is not valid as a URI or as a prefixed URI.
• The constraint value UriStem implies a constraint value that is a URI or prefixed URI, but none is provided.

If URIs are enclosed URIs in angle brackets, the brackets are stripped away.

shapeID	propertyID	value_type	constraint_value	constraint_type
:book	dct:subject		<https://id.loc.gov/subjects>	UriStem
:book	dct:creator	URI	<https://www.wikidata.org/wiki/Q46914185>

This is interpreted as:

DCAP
    Shape
        shapeID: :book
        start: True
        Statement
            propertyID: dct:subject
            constraint_value: https://id.loc.gov/subjects
            constraint_type: UriStem
        Statement
            propertyID: dct:creator
            value_type: URI
            constraint_value: https://www.wikidata.org/wiki/Q46914185