Getting started

Configuring a Traversal Execution Profile

The DSE Graph extension takes advantage of execution profiles to allow different configurations for the various query handlers.

You can specify the default execution profile to set the graph name and any graph option and use it like in the following example:

const dse = require('dse-driver');
const dseGraph = require('dse-graph');

const client = new dse.Client({
  contactPoints: ['host1', 'host2'],
  profiles: [
    new dse.ExecutionProfile('default', { graphOptions:  { name: 'my_graph' } })
  ]
});

const g = dseGraph.traversalSource(client);
// Print the names of john's friends
g.V().has('name','john').out('friends').values('name').toList()
  .then(names => names.forEach(console.log));

If you have multiple execution profiles, you can also specify it when obtaining the TraversalSource instance:

const g = dseGraph.traversalSource(client, { executionProfile: 'graph-oltp2' });

Visit the Execution Profiles documentation and the Execution Profile API docs on the DSE driver for more information.

Graph Traversal Executions via a DSE Driver Client

Queries generated from Traversal can also be explicitly executed using the existing client.executeGraph() method on the DSE Driver. executeGraph() method returns results using DSE Graph types. If you are familiar to DSE driver query execution, you might prefer that way.

To generate the query from the traversal, use the queryFromTraversal() method:

const query = dseGraph.queryFromTraversal(g.V().hasLabel('person'));

For the DSE driver to properly execute a query generated from a Traversal, you must use an Execution Profile generated using createExecutionProfile() method.

const client = new dse.Client({
  contactPoints: ['host1', 'host2'],
  profiles: [
    dseGraph.createExecutionProfile('explicit-exec-graph1')
  ]
});

const g = dseGraph.traversalSource(client);

const query = dseGraph.queryFromTraversal(g.V().hasLabel('person'));
// Reference the execution profile previously created.
client.executeGraph(query, null, { executionProfile: 'explicit-exec-graph1' })
  .then(result => {
    for (const vertex of result) {
      console.log(vertex.label); // person
      console.log(vertex instanceof dse.Graph.Vertex); // true
    }
  });

Putting it all together

const dse = require('dse-driver');
const dseGraph = require('dse-graph');
const client = new dse.Client({
  contactPoints: ['host1', 'host2'],
  profiles: [
    new dse.ExecutionProfile('default', { graphOptions:  { name: 'my_graph' } }),
    dseGraph.createExecutionProfile('explicit-exec', { graphOptions:  { name: 'my_graph' } } )
  ]
});

// Obtain a traversal source
const g = dseGraph.traversalSource(client);

// Execute queries using the Traversal toList() method
g.V().hasLabel('person').values('age').toList()
  .then(ages => ages.forEach(console.log));

// Alternatively you can convert a given traversal to a string query and use 
// the DSE Driver executeGraph() method
const query = dseGraph.queryFromTraversal(g.V().hasLabel('person').values('age'));
// Reference the execution profile previously created.
client.executeGraph(query, null, { executionProfile: 'explicit-exec' })
  .then(result => console.log(result.toArray()));