A labeled property graph (LPG) is a type of graph database.
In LPG-style databases the graph is comprised of nodes and relationships. Each node or relationship has an ID tag, one or more “labels” describing its type or class, and a set of “properties” that present values and a corresponding key to allow referencing.
Intuitively, two nodes are always joined by a relationship to form the larger structure of the graph.
There is no standardised query language for all LPG-style databases, but Cypher is the most widely adopted one.
We could retrieve information about the example above using a Cypher query like this:
RETURN person1, relationship, person2