function to find concise bounded graph for SPARQL Updates #7
Description
When a PATCH request using SPARQL Update contains a subject with a blank node, then INSERT DATA and DELETE DATA cannot work ( unless the relation is an owl:InverseFunctionalProperty ). In that case one must calculate the Concise Bounded Description of the graph and put that in the WHERE clause. So one needs to calculate this CBD.
( not checked exactly if CBD is the right relation )
for example in FOAF foaf:mbox is an owl:inverseFunctionalProperty. In that case
the server could in fact delete all the correct blank nodes for the following request
DELETE DATA { [] foaf:mbox <mailto:henry.story@bblfish.net> . }But for an graph such as
<#me> contact:home [ a contact:ContactLocation;
contact:address [ contact:city "Fontainebleau";
contact:country "France";
contact:postalCode "77300";
contact:street "21 rue Saint Honore"
];
];
contact:work [ a contact:ContactLocation;
contact:address [ contact:city "Fontainebleau";
contact:country "France";
contact:postalCode "77300";
contact:street "21 rue Saint Merry"
];
];
contact:work [ a contact:ContactLocation;
contact:address [ contact:city "Fontainebleau";
contact:country "France";
contact:postalCode "77300";
contact:street "23 rue Saint Merry"
];
] .The replacing the postalCode cannot be done like this
DELETE DATA { [] contact:postalCode "77300" }
INSERT DATA { [] contact:postalCode "77305" }because the server would not know
- which triple in the above graph to remove. ( the one for the home address or the one for the work address ? )
- where to put the new triple ( does it even get attached to an address? )
So really one needs a query such as the following:
DELETE { ?add contact:postalCode "77300" }
INSERT { ?add contact:postalCode "77300" }
WHERE {
?add contact:city "Fontainebleau";
contact:country "France";
contact:postalCode "77300";
contact:street "21 rue Saint Merry"
}But this works only because we are here assuming that contact:city, contact:country, contact:postalCode and contact:street form an owl:key .
If these four relations did not form an owl:key then one would have to at leat try to add as many relations to the WHERE clause to make the update identify one object in that particular graph.