Issues with Creating Vertex and Edges in Titan Graph Database

Question

I am trying to create vertex and edges in Titan graph database (Titan1.0.0)..

gremlin> graph = TitanFactory.open('titan-1.0.0-hadoop1/conf/titan-cassandra-es.properties')

gremlin> t1 = graph.addVertex(label, "Testbed", "Name", "testbed1","Status","A","TId",101)
==>v[1228816568]

gremlin> r2= graph.addVertex(label, "Router", "RStatus","F","RId",1002, "TId", 101)
==>v[3686424680]

gremlin> t1.addEdge("tbConRtr", r2)
==>e[kblqtz-kblsxk-d6vp-1oysvhk][1228816568-tbConRtr->3686424680]

Questions:

1) Why is the vertex number returned here are not sequence and it is some random number? For addEdge step also it is creating edge with some random value (kblqtz-kblsxk-d6vp-1oysvhk)

e[kblqtz-kblsxk-d6vp-1oysvhk][1228816568-tbConRtr->3686424680]

2) I want my TId value should be unique I have tried the following and got Error Msg:

gremlin> mgmt.buildIndex("TId",Vertex.class).addKey(TId).unique().buildCompositeIndex();
No such property: TId for class: groovysh_evaluate

How can I create a unique property value in Titan database?

Kindly help me to resolve this.

Answer 1

1. Vertex ids and edge ids are generated and assigned by Titan. If you want to have your own identifier, you should define a property and index it.

2. The error No such property: TId indicates that you are trying to use a variable TId that has not been initialized. You should define the vertex property before trying to index it

   gremlin> graph = TitanFactory.open('conf/titan-cassandra-es.properties')
   ==>standardtitangraph[cassandrathrift:[127.0.0.1]]
   gremlin> mgmt = graph.openManagement()
   ==>com.thinkaurelius.titan.graphdb.database.management.ManagementSystem@4b97b3d2
   gremlin> TId = mgmt.makePropertyKey("TId").dataType(Integer.class).cardinality(Cardinality.SINGLE).make()
   ==>TId
   gremlin> mgmt.buildIndex("TId",Vertex.class).addKey(TId).unique().buildCompositeIndex()
   ==>TId
   gremlin> mgmt.commit()
   ==>null
   gremlin> t1 = graph.addVertex(label, "Testbed", "Name", "testbed1","Status","A","TId",101)
   ==>v[4200]
   gremlin> r2= graph.addVertex(label, "Router", "RStatus","F","RId",1002, "TId", 101)
   Adding this property for key [TId] and value [101] violates a uniqueness constraint [TId]
   

Please refer to the Titan documentation on schema and data modeling and also indexing for better performance.