titan.md

gistfile1.txt

# Apache Titan

[http://thinkaurelius.github.io/titan/](http://thinkaurelius.github.io/titan/)

### What is it?

They sell it as a scalable graph database optimized for storing and querying graphs containing hundreds of billions AND TRILLIONS of vertices and edges distributed across a multi-machine cluster.

So if that's true, we should be able to use at WHI.

---

### Some Features


* Support for various storage backends including **Cassandra**.

* Native integration with the [TinkerPop](http://www.tinkerpop.com) graph stack.
	* Gremlin: a domain specific language for traversing property graphs.
	* Rexster: a graph server that exposes any Blueprints graph through several mechanisms with a general focus on REST.

* A lot more ...

----

### Basic Introduction with Cassandra.

Create a graph

```xml
<graph>
	<graph-name>demo</graph-name>
	<properties>
	    <storage.backend>cassandra</storage.backend>
	    <storage.keyspace>demo</storage.keyspace>
	</properties>
</graph>
```

---

Add a few Vertices

```ruby
justin = g.addVertex(null, [ name: "Justin", type: "user" ])
selena = g.addVertex(null, [ name: "Selena", type: "user" ])
efron = g.addVertex(null, [ name: "Efron", type: "user" ])
pony = g.addVertex(null, [ name: "My Little Pony", type: "entry" ])
```

Add a few Edges

```ruby
g.addEdge(justin, pony, "hearted")
g.addEdge(selena, pony, "hearted")
```

Commit your changes!

```ruby
g.commit()
```

---

Simple operations traversing the graph

```ruby
justin.out("hearted").map
# ==> { name=My Little Pony, type=entry }
selena.out("hearted").map
# ==> { name=My Little Pony, type=entry }
selena.out("friend").out("hearted").map

g.commit()

g.addEdge(selena, justin, "friend")
selena.out("friend").out("hearted").map
# ==> { name=My Little Pony, type=entry }
```

---

### Helen

Manipulate and traverse Titan graphs via Rexster.

[github.com/jpemberthy/helen](http://github.com/jpemberthy/helen)