边和属性的综合索引（tinkerpop / orientDB）

Question

I have a graph in OrientDB (uses Tinkerpop stack), and need to enable very fast lookups of edge values / properties / fields and edge in/out vertices.

So, basically the user will need to lookup as follows:

SELECT FROM myEdges WHERE inVertex = {VertexIdentity}, outVertex = {VertexIdentity}, property1 = 'xyz'

Essentially it's a composite index for the edge class, of 3 properties: inVertex, outVertex & property1

Basically - if the user already has a VertexIdentity for 2 vertices (maybe, in the form: #CLUSTER_ID:RECORD_ID) - and the the property value (in this case, xyz ) - it will allow very fast lookup to see if the combination already exists in the graph (if 2 vertices are linked with property1) - without making a traversal.

So far I found the following code to help with composite indexes, but I cant see if it's possible to include in/out vertices in this (for a graph edge).

https://github.com/orientechnologies/orientdb/blob/master/tests/src/test/java/com/orientechnologies/orient/test/database/auto/SQLSelectCompositeIndexDirectSearchTest.java

Is it possible??

Answer 1

This is working fine for defining edge uniqueness:

OCommandSQL declareIn= new OCommandSQL();
declareIn.setText("CREATE PROPERTY E.in LINK");
OCommandSQL declareOut= new OCommandSQL();
declareOut.setText("CREATE PROPERTY E.out LINK");
OCommandSQL createIndexUniqueEdge= new OCommandSQL();
createIndexUniqueEdge.setText("CREATE INDEX unique_edge ON E (in, out) UNIQUE");
graph.command(declareIn).execute();
graph.command(declareOut).execute();               
graph.command(createIndexUniqueEdge).execute();

In you case just add another property to the Edge class and consequently in the index

Answer 2

You can do it with OrientDB, just create the composite index against the in and out properties too (declare them in E class before).

This is used also as constraints to avoid multiple edges connect the same vertices.