Graph support

IDseSession has dedicated methods to execute graph queries:

using Dse.Graph;

session.ExecuteGraph("system.createGraph('demo').ifNotExist().build()");

GraphStatement s1 = new SimpleGraphStatement("g.addV(label, 'test_vertex')").SetGraphName("demo");
session.ExecuteGraph(s1);

GraphStatement s2 = new SimpleGraphStatement("g.V()").SetGraphName("demo");
GraphResultSet rs = session.ExecuteGraph(s2);
Vertex vertex = rs.First();
Console.WriteLine(vertex.Label);

Graph options

You can set default graph options when initializing the cluster. They will be used for all graph statements. For example, to avoid repeating SetGraphName("demo") on each statement:

IDseCluster dseCluster = DseCluster.Builder()
    .AddContactPoint("127.0.0.1")
    .WithGraphOptions(new GraphOptions().SetName("demo"))
    .Build();

If an option is set manually on a GraphStatement, it always takes precedence; otherwise the default option is used. This might be a problem if a default graph name is set, but you explicitly want to execute a statement targeting system, for which no graph name must be set. In that situation, use GraphStatement.SetSystemQuery():

GraphStatement s = new SimpleGraphStatement("system.createGraph('demo').ifNotExist().build()")
    .SetSystemQuery();
session.ExecuteGraph(s);

Asynchronous query execution

Graph statements can also be executed without blocking the calling thread using ExecuteGraphAsync() method.

GraphResultSet rs = await session.ExecuteGraphAsync(new SimpleGraphStatement("g.V()"));

Handling results

Graph queries return a GraphResultSet, which is essentially an enumerable of GraphNode:

GraphResultSet rs = session.ExecuteGraph(new SimpleGraphStatement("g.V()"));

// Iterating as GraphNode
foreach (GraphNode n in rs)
{
    Console.WriteLine(n);
}

GraphNode represent a response item returned by the server. You can cast the result to a specific type as it implements implicit conversion operators to Vertex, Edge and Path:

GraphResultSet rs = session.ExecuteGraph(new SimpleGraphStatement("g.V()"));

// Iterating as Vertex
foreach (Vertex vextex in rs)
{
    Console.WriteLine(vertex.Label);
}

GraphNode also provides conversion methods for scalar values like ToDouble(), ToInt32(), To<T>() and ToString():

GraphNode r = session.ExecuteGraph(new SimpleGraphStatement("g.V().count()")).First();
Console.WriteLine("The graph has {0} vertices.", r.ToInt32());

GraphNode inherits from DynamicObject, allowing you to consume it using the dynamic keyword and/or as a dictionary.

dynamic r = session.ExecuteGraph(new SimpleGraphStatement("g.V()")).First();

Parameters

Graph query parameters are always named. Parameter bindings are passed as an anonymous type or as a IDictionary<string, object> alongside the query:

session.ExecuteGraph("g.addV(label, vertexLabel)", new { vertexLabel = "test_vertex_2" });

Note that, unlike in CQL, Gremlin placeholders are not prefixed with “:”.

Prepared statements

Prepared graph statements are not supported by DSE Graph yet (they will be added in the near future).