I am trying to write a SHACL constraint for a date comparison where the start date must be less than or equal to an end date. When the dates are attached to the same node using the :beginDate
and :endDate
predicates, the constraint is straight forward:
:StartEndRuleShape a :PropertyShape ;
sh:path :beginDate ;
sh:lessThanOrEquals :endDate ;
sh:message "Begin Date is after End Date." .
The real world model is more complex. In the attached diagram, note how an :AnimalSubject
hasReferenceInterval
. ReferenceInterval IRIs have a :ReferenceBegin
and a :ReferenceEnd
, which are in turn assigned the date value using the time:inXSDDate
predicate. How can I apply the constraint in this case to ensure the ReferenceBegin value is equal to or less than ReferenceEnd value? Is this a case for using SHACL-SPARQL, or sequencePath ? I've been unable to find good examples of either. Cheers!
I tested the following SHACL-SPARQL on data that violates the constraint: ReferenceBegin = "2016-12-07", ReferenceEnd = "2016-12-06", but the Validation Report does not detect the violation. If I run the SPARQL on its own, it does pick out the observation. Any thoughts on why? I am using Stardog/Stardog Studio and have also posted on their user support platform.
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix sh: <http://www.w3.org/ns/shacl#> .
@prefix time: <http://www.w3.org/2006/time#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix : <http://foo.bar.org/> .
:IntervalShape a sh:NodeShape ;
sh:targetClass :ReferenceInterval ;
sh:sparql [
a sh:SPARQLConstraint ;
sh:message "End Date must be greater than or equal to Begin Date";
sh:prefixes [
sh:declare [
sh:prefix "time" ;
sh:namespace "http://www.w3.org/2006/time#"^^xsd:anyURI ;
]
] ;
sh:select
"""SELECT $this (?beginDate AS ?intervalStart) (?endDate AS ?intervalEnd)
WHERE {
$this :hasReferenceInterval ?interval .
?interval :ReferenceBegin ?beginIRI ;
:ReferenceEnd ?endIRI .
?beginIRI time:inXSDDate ?beginDate .
?endIRI time:inXSDDate ?endDate .
FILTER (! (?endDate >= ?beginDate ))
}""" ;
] .
It looks like your constraint has two issues:
You declare the time
prefix in your SHACL, but not the base
prefix. You want:
sh:prefixes [ sh:declare [ sh:prefix "time" ; sh:namespace "http://www.w3.org/2006/time#"^^xsd:anyURI ; ], [ sh:prefix "" ; sh:namespace "http://foo.bar.org/"^^xsd:anyURI ; ] ] ;
Your focus node is :ReferenceInterval
, however the way your query is written, $this
will only ever be bound to entities that :hasReferenceInterval [a :ReferenceInterval]
. I rewrote the query so that ?interval
is now $this
as follows:
sh:select """SELECT $this (?beginDate AS ?intervalStart) (?endDate AS ?intervalEnd) WHERE { $this :ReferenceBegin ?beginIRI ; :ReferenceEnd ?endIRI . ?beginIRI time:inXSDDate ?beginDate . ?endIRI time:inXSDDate ?endDate . FILTER (! (?endDate >= ?beginDate )) }""" ;
Adding this constraint, I was able to see a violation.
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