Adapt the User Graph Creation Solution

src/SQL2Linked/Implementations/UserStructuralData.cs

@@ -2,54 +2,50 @@
 using Coscine.Database.Models;
 using Coscine.Metadata;
 using VDS.RDF;
-using VDS.RDF.Query;
 
 namespace SQL2Linked.Implementations
 {
     public class UserStructuralData : StructuralData<User, UserModel>
     {
         public readonly string UserUrlPrefix = "https://purl.org/coscine/users";
-        public readonly Uri FoafPerson = new Uri("http://xmlns.com/foaf/0.1/Person");
+        public readonly Uri RdfType = new("http://www.w3.org/1999/02/22-rdf-syntax-ns#type");
+        public readonly Uri FoafPerson = new("http://xmlns.com/foaf/0.1/Person");
 
         public override IEnumerable<IGraph> ConvertToLinkedData(IEnumerable<User> entries)
         {
             var graphs = new List<IGraph>();
 
-            foreach (User entry in entries)
+            foreach (var entry in entries)
             {
-                string userGraphName = $"{UserUrlPrefix}/{entry.Id}";
-                IGraph graph = RdfStoreConnector.GetGraph(userGraphName);
+                var userGraphName = $"{UserUrlPrefix}/{entry.Id}";
+                var graph = RdfStoreConnector.GetGraph(userGraphName);
 
                 // check if a triple with a foaf:Person already exists in the user graph
                 var getTriples = graph.GetTriplesWithObject(FoafPerson);
 
-                if (getTriples.Count() == 0)
+                if (!getTriples.Any())
                 {
                     // check if a user graph already exists
-                    bool exists = RdfStoreConnector.HasGraph(userGraphName);
+                    var exists = RdfStoreConnector.HasGraph(userGraphName);
 
                     if (!exists)
                     {
                         RdfStoreConnector.CreateNamedGraph(userGraphName);
                     }
 
-                    // extend graph by triple https://purl.org/coscine/users/{userId} a foaf:Person
-                    var commandString = new SparqlParameterizedString
-                    {
-                        CommandText = @"INSERT
-                                {
-                                    GRAPH @userGraphName
-                                    {
-                                        [
-                                            a foaf:Person ;
-                                        ]
-                                    }
-                                }"
-                    };
+                    graph.Assert(
+                        new Triple(
+                            graph.CreateBlankNode(),
+                            graph.CreateUriNode(RdfType),
+                            graph.CreateUriNode(FoafPerson)
+                        )
+                    );
 
-                    commandString.Namespaces.AddNamespace("foaf", FoafPrefixUrl);
-                    commandString.SetUri("userGraphName", new Uri(userGraphName));
-                    QueryEndpoint.QueryRaw(commandString.ToString());
+                    Console.WriteLine($"Will migrate user '{entry.DisplayName}' with id '{entry.Id}'.");
+                }
+                else
+                {
+                    Console.WriteLine($"Will NOT migrate user '{entry.DisplayName}' with id '{entry.Id}'.");
                 }
                 graphs.Add(graph);
             }

src/SQL2Linked/StructuralData.cs

@@ -2,7 +2,6 @@
 using Coscine.Database.Models;
 using Coscine.Metadata;
 using VDS.RDF;
-using VDS.RDF.Query;
 
 namespace SQL2Linked
 {
@@ -11,15 +10,12 @@ namespace SQL2Linked
         public T Model { get; init; }
         public ConsulConfiguration Configuration { get; init; }
         public RdfStoreConnector RdfStoreConnector { get; init; }
-        public readonly SparqlRemoteEndpoint QueryEndpoint;
-        public readonly Uri FoafPrefixUrl = new Uri("http://xmlns.com/foaf/0.1/");
 
         public StructuralData()
         {
             Configuration = new ConsulConfiguration();
             RdfStoreConnector = new RdfStoreConnector(Configuration.GetStringAndWait("coscine/local/virtuoso/additional/url"));
             Model = new T();
-            QueryEndpoint = new SparqlRemoteEndpoint(new Uri(string.Format("http://localhost:8890/sparql")));
         }
 
         public abstract IEnumerable<IGraph> ConvertToLinkedData(IEnumerable<S> entries);