Delete all triples about event time except earliest event time - sparql

Question

I have several triples like this
:event1 :hasTimeStamp "2017-06-30T00:01:00Z" .
:event1 :hasTimeStamp "2017-06-30T00:02:00Z" .
:event1 :hasTimeStamp "2017-06-30T00:03:00Z" .
I would like to delete all of the assertions about :event1's timestamp except the earliest.
I know how to select the earliest, insert it into a scratch named graph, delete all :event1 timestamps, and then copy back from the scratch graph.
Is there a way to do the deletion in place, with no utilization of a temporary/scratch graph?
Here's a nested select, where the inner subselect gets the minimum time, which is then be compared with the individual times form the outer select.
Now I just have to wrap that in the delete.
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
SELECT *
WHERE
{ ?s rdf:type <http://turbo.org/procStartTimeMeas> ;
<http://purl.obolibrary.org/obo/IAO_0000136> ?something .
?something <http://purl.obolibrary.org/obo/RO_0002223> ?another .
?another rdf:type <http://turbo.org/R2RInstantiation> .
?s <http://purl.obolibrary.org/obo/IAO_0000004> ?o
{ SELECT ?s (MIN(?o) AS ?earliest)
WHERE
{ ?s rdf:type <http://turbo.org/procStartTimeMeas> ;
<http://purl.obolibrary.org/obo/IAO_0000136> ?something .
?something <http://purl.obolibrary.org/obo/RO_0002223> ?another .
?another rdf:type <http://turbo.org/R2RInstantiation> .
?s <http://purl.obolibrary.org/obo/IAO_0000004> ?o
}
GROUP BY ?s
}
FILTER ( ?o != ?earliest )
}

Answer 1

Try this (not in the production environment):
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
DELETE {
?s <http://purl.obolibrary.org/obo/IAO_0000004> ?o2 .
}
WHERE {
?s <http://purl.obolibrary.org/obo/IAO_0000004> ?o2 .
?s rdf:type <http://turbo.org/procStartTimeMeas> .
FILTER EXISTS {
?s <http://purl.obolibrary.org/obo/IAO_0000004> ?o1 .
?s rdf:type <http://turbo.org/procStartTimeMeas> .
FILTER (?o2 > ?o1)
}
}
I'm not sure I understand correctly what these predicates mean.
I suppose <http://purl.obolibrary.org/obo/IAO_0000004> is :hasTimeStamp of the initial example.
In my answer, ?s rdf:type <http://turbo.org/procStartTimeMeas> is the only selection criterion. Please add other criteria.

Answer 2

(An alternative to the nice solution of #StansilavKralin)
I just did it based on the sample data
#prefix : <http://example.org/> .
#prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
:event1 :hasTimeStamp "2017-06-30T00:01:00Z"^^xsd:dateTime .
:event1 :hasTimeStamp "2017-06-30T00:02:00Z"^^xsd:dateTime .
:event1 :hasTimeStamp "2017-06-30T00:03:00Z"^^xsd:dateTime .
Not sure whether this is what you want, but at least it's pretty compact and I'm a big fan of MINUS which is at least more human readable (but maybe less performant):
PREFIX : <http://example.org/>
DELETE {
?event :hasTimeStamp ?ts .
}
WHERE
{ ?event :hasTimeStamp ?ts
MINUS
{ { SELECT ?event (MIN(?_ts) AS ?ts)
WHERE
{ ?event :hasTimeStamp ?_ts }
GROUP BY ?event
}
}
}

Answer 3

I think this does what I want, but I'd like to see suggestions from others. I don't want to be reckless with a deletion.
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
DELETE {
?s <http://purl.obolibrary.org/obo/IAO_0000004> ?o .
}
WHERE
{ SELECT *
WHERE
{ ?s rdf:type <http://turbo.org/procStartTimeMeas> ;
<http://purl.obolibrary.org/obo/IAO_0000136> ?something .
?something <http://purl.obolibrary.org/obo/RO_0002223> ?another .
?another rdf:type <http://turbo.org/R2RInstantiation> .
?s <http://purl.obolibrary.org/obo/IAO_0000004> ?o
{ SELECT ?s (MIN(?o) AS ?earliest)
WHERE
{ ?s rdf:type <http://turbo.org/procStartTimeMeas> ;
<http://purl.obolibrary.org/obo/IAO_0000136> ?something .
?something <http://purl.obolibrary.org/obo/RO_0002223> ?another .
?another rdf:type <http://turbo.org/R2RInstantiation> .
?s <http://purl.obolibrary.org/obo/IAO_0000004> ?o
}
GROUP BY ?s
}
FILTER ( ?o != ?earliest )
}
}