Both nodes and relationships are understood to be "property containers" which behave as maps (can access the value of a given key) but lack some other access methods. Sometimes (for introspection, or migration, or data harmonization) it is useful to separately access the key, value, or key/value pair.
Possible functions:
MATCH n RETURN keys(n)
Returns the collection of property keys.
MATCH n RETURN values(n)
Returns the collection of property values.
MATCH n RETURN entries(n)
Returns a collection of key/value pairs.
Forked from a discussion on github: neo4j/neo4j: Issue #164