The main reason for using indexes in a graph database is to find the starting point in the graph as fast
as possible. After that seek you rely on in-graph structures and the first class citizenship of
relationships in the graph database to achieve high performance. Thus graph queries themselves do
not need indexes to run fast.
Indexes can be added at any time. Note that it will take some time for an index to come online when
there’s existing data.
Normally you don’t specify indexes when querying for data. They will be used automatically.
This means we that can simply look up the Tom Hanks node, and the index will kick in behind
the scenes to boost performance.
Chapter 17. Legacy indexing
Chapter 18. Unique indexing
6.10. Configuration and fulltext indexes
2.2.5. Constraints and indexes
 https://neo4j.com/docs/rest-docs/3.1/ neo4j 3.1
 https://neo4j.com/docs/java-reference/current/#indexing-create-advanced neo4j 2.3.3
 http://neo4j.com/docs/stable/indexing-create-advanced.html# neo4j 2.3.3