Re: How to call CREATE / DELETE GRAPH in Fuseki

[Andy Seaborne]

It's DROP not DELETE in SPARQL Update.

DELETE is for triples, DROP is for whole graphs.
http://www.w3.org/TR/sparql11-update/#graphManagement

On 31/07/14 22:47, Arthur Keen wrote:
For executing CREATE or DELETE GRAPH in Fuseki
I tried to use them the same way as SPARQL INSERT/DELETE by posting to 
../ds/update, but this did not work

Which Endpoint URL pattern I should use:
http://localhost:8080/ds/update,
http://localhost:8080/ds/graph

There are two things here:

1/ SPARQL Update -- CREATE and DROP -- use the "update" endpoint

2/ SPARQL Graph Store Protocol -- this is not SPARQL Update -- use a 
writeable GSP endpoint.

GSP is normal HTTP usage on web resource GET/PUT/POST/DELETE/HEAD

http://www.w3.org/TR/sparql11-http-rdf-update/

what that document does is really explain how the REST(ish) use of HTTP 
applies to graph store.  It isn't defining anything new except the 
naming scheme for graphs.

In GSP, the app (HTTP) PUT RDF syntax (Turtle, N-triples, JSON-LD) to 
create or replace the contents of a graph and POST to create or add to a 
graph.

HTTP DELETE deletes a web resource as normal.


For Creating a graph do you use an http put or post request?
For deleting a graph do you use an http delete request

And the name of the variable to bind the query to.  Using query, update, etc as 
variable names, see commented out lines of code below
Thanks very much,

They don't take variables.

Just do e.g.

INSERT DATA { GRAPH :g { :s :p :o } }

and a graph is created for :g

INSERT
{ GRAPH ?g { :s :p :o } }
WHERE
{ ... ?g ... }

Whether CREATE is necessary in other situations depends on the storage
implementation. In Fuseki, with all the Jena provided storage
alternative, it is not needed.

It's possible other storage layers need graphs creating beforehand. I
don't know of any. In a quad store, it's fairly irrelevant distinction.


Any guidance would be much appreciated

Arthur

        Hope that makes it clearer,
        Andy

For context, here is the node.js code that I am using to call fuseki, with 
commented out variations of httpreq that I have tried

//http://localhost:3000/graph/create?graphName=http://testGraph
  app.get('/api/graph/create', function(req, res){
    var update = "CREATE SILENT GRAPH <?:graphName>";
    var graphName = req.param("graphName");
    update = update.replaceAll("?:"+"graphName", graphName);
            //httpreq.post(endpoint.getUpdateURL(), {parameters: {update: 
update}}, function (geterr, getres){
            //httpreq.post(endpoint.getGraphURL(), {parameters: {update: 
update}}, function (geterr, getres){
        httpreq.put(endpoint.getGraphURL(), {parameters: {query: update}}, 
function (geterr, getres){
            if (geterr) return console.log(geterr);
          res.send(endpoint.getGraphURL()+"   "+ update+"   "+ graphName);
        });
    });

//http://localhost:3000/graph/delete?graphName=http://testGraph

If you are using the default naming /delete and /create don't exist as 
services.


app.get('/graph/delete', function(req, res) {
     var update = "DELETE SILENT GRAPH <?:graphName>";
     var graphName = req.param("graphName");
     update = update.replaceAll("?:" + "graphName", graphName);
     //httpreq.post(endpoint.getUpdateURL(), {parameters: {update: update}}, 
function(geterr, getres) {
     httpreq.delete(endpoint.getGraphURL(), {parameters: {graph: update}}, 
function(geterr, getres) {
         if (geterr)
             return console.log(geterr);
         console.log(update);
         res.send(endpoint.getGraphURL());
     });
});


If you want security, you can either front Fuseki with httpd/nginx 
(that's advisable anyway for any java web container), or wait for Fuseki2.

        Andy