在neo4j cypher中检索确切的节点ID

Question

I'm using neo4j-jdbc 2.3.2 as my neo4j client for java. When I executed following cypher query
match(p:Person) where p.id_number='761201948V' return p.id;
it will return P2547228 as node id. I feel like id is same as other properties of the node as I can use it inside where clauses.

But here I'm expecting an integer which can use inside this query START p=node('node.id') return p; Is this id is an internal thing to neo4j db? and is there a way to retrieve this id?

From the following two cyphers what is most efficient one?(if both referring same node)

1. START p=node('2547223') return p;
2. match(p:Person) where p.id='P2547228' return p;

Answer 1

You have to use the ID(x) function for this. Note, that ID(x) and x.id are a complete different thing. The former returns the internal node/relationship id managed by Neo4j itself. The latter gives the id property which is managed by the user and not by the database itself.

Also note, that a node/relationship ID is always numeric.

Using START is pretty much old school and shouldn't be used any more (except for accessing manual indexes):

start p=node(2547228) return p 

This one is a equivalent statement. It is highly efficient since it just needs to do a simple seek operation on the node store:

match(p:Person) where id(p)=2547228 return p;

Looking for a property requires either a node label scan or a schema index lookup:

match(p:Person) where p.id=2547228 return p;

Just check out the query plans on your own by prefixing the statement with PROFILE .