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Using Cypher, how can I find a node where a property doesn't exist?
For example, I have two nodes:
A = {foo: true, name: 'A'}, B = { name: 'B'} Now I'd like to find B, selecting it on the basis of not having the foo property set. How can I do this?
455
In Neo4j, since there is no table schema or equivalent to restrict possible properties, non-existence and null are equivalent for node and relationship properties. That is, there really is no such thing as a property with a null value; null indicates that the property doesn't exist at all.
You can change the nodes associated with a label but you can't change the type of a relationship.
An OPTIONAL MATCH matches patterns against your graph database, just like a MATCH does. The difference is that if no matches are found, OPTIONAL MATCH will use a null for missing parts of the pattern. OPTIONAL MATCH could be considered the Cypher equivalent of the outer join in SQL.
As Michael Hunger mentioned
MATCH (n) WHERE NOT EXISTS(n.foo) RETURN n On older versions of Neo4j you can use HAS:
# Causes error with later versions of Neo4j MATCH (n) WHERE NOT HAS(n.foo) RETURN n If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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