Creating a relationship

In order to create a relationship, we have to tell Neo4j about its start and end node, meaning the nodes need to be already in the database when creating the relationship. There are two possible solutions:

• Create nodes and the relationship(s) between them in one pass:

CREATE (n:Label {id: 1})
CREATE (m:Label {id: 2})
CREATE (n)-[:RELATED_TO]->(m)

• Create the nodes (if they don't already exist):

CREATE (:Label {id: 3})
CREATE (:Label {id: 4})

And then create the relationship. In that case, since the relationship is created in another query (another namespace), we need to first MATCH the nodes of interest:

MATCH (a {id: 3})
MATCH (b {id: 4})
CREATE (a)-[:RELATED_TO]->(b)

While nodes are identified with brackets, (), relationships are characterized by square brackets, [].

If we check the content of our graph after the first query, here is the result:

Reminder: while specifying a node label when creating a node is not mandatory, relationships must...