“自描述” Neo4j 图数据库（第 1 部分）

CREATE (:MAN {name: "Joe"}) - [:BITES] -> (:DOG {name: "Fido"})

CREATE
	(man:META:Nodes {type: "MAN", name: "MAN"}),
	(dog:META:Nodes {type: "DOG", name: "DOG"}),
	news = (man - [:FROM_NODE] ->
		(:META:Relationships {type: "BITES", name: "BITES"})
		- [:TO_NODE] -> dog)

// Create a tips to be tested...
//
	// Tip 1: "Joe bites Fido." (Case: Known incident already in data)
MATCH (joe:MAN {name: "Joe"}) - [known_bite:BITES] -> (fido:DOG {name: "Fido"})
SET known_bite.status = "unconfirmed"
	// Tip 2: "Fido bites Joe." (Case: Known actors, role mismatch)
MERGE fido - [:BITES {status: "unconfirmed"}] -> joe
	// Tip 3: "Johnny bites Rover." (Case: Unknown actors, fact check assist)
CREATE (:UNK {name: "Johnny"}) - [:BITES {status: "unconfirmed"}] -> (:UNK {name: "Rover"})
WITH known_bite

// Let's see how our metamodel can help us figure out about the newsworthiness
// of these biting incident tips.
//
// First, let's find out what we know about biting incidents...
MATCH (biter) --> (bites:META:Relationships {type: "BITES"}) --> (bitee)
WITH biter, bites, bitee

// Now, round up our unconfirmed tips of bite incidents and investigate their newsworthiness...
MATCH (accused_biter) - [incident:BITES {status: "unconfirmed"}] -> (alleged_victim)
WITH biter, bites, bitee, accused_biter, incident, alleged_victim,
	accused_biter.name + " " + lower(type(incident)) + " " + alleged_victim.name + "." as unconfirmed_tip,
	// First, fact-check the accused Biter...
	CASE
	    WHEN "UNK" IN labels(accused_biter)
		THEN "Biter: FACT CHECK - Need to confirm " + accused_biter.name + " is a " + biter.type + ". Otherwise, no news."
		// We have a potentially newsworthy biter...
	    WHEN biter.type IN labels(accused_biter)
		THEN "Biter: CONFIRMED - " + accused_biter.name + " is a " + biter.type + "."
		// The known Biter is of the wrong type, no news...
		WHEN NOT (biter.type IN labels(accused_biter))
		THEN "Biter: NO NEWS - " + accused_biter.name + " is NOT a " + biter.type + "."
		// Unhandled case - The metamodel might need refining...
		ELSE "Biter: ALERT - I am confused about " + accused_biter.name + "'s role in this biting incident. A report is being logged to the Metamodel Police. Nothing to see here. Step away from the program. This just became a crime scene..."
		END as biter_assessment,
	// Next, check the alleged victim...
	CASE
	    WHEN "UNK" IN labels(alleged_victim)
		THEN "Victim: FACT CHECK - Need to confirm " + alleged_victim.name + " is a " + bitee.type + ". Otherwise, no news."
		// We have a potentially newsworthy alleged_victim...
	    WHEN biter.type IN labels(accused_biter) AND bitee.type IN labels(alleged_victim)
		THEN "Victim: CONFIRMED - " + alleged_victim.name + " is a " + bitee.type + ".<br>CONGRATULATIONS! We have NEWS! :-)"
		// If both actors are appropriate, we have a newsworthy tip! :-)
	    WHEN bitee.type IN labels(alleged_victim)
		THEN "Victim: CONFIRMED - " + alleged_victim.name + " is a " + bitee.type + "."
		// The known alleged_victim is of the wrong type, no news...
		WHEN NOT (bitee.type IN labels(alleged_victim))
		THEN "Victim: NO NEWS - " + alleged_victim.name + " is NOT a " + bitee.type + "."
		// Unhandled case - The metamodel might need refining...
		ELSE "Victim: ALERT - I am confused about " + alleged_victim.name + "'s role in this biting incident. A report is being logged to the Metamodel Police. Nothing to see here. Step away from the program. This just became a crime scene..."
		END as bitee_assessment

RETURN unconfirmed_tip as `Tip`, biter_assessment + " <br> " + bitee_assessment as `Tip Assessment Results`

MATCH (accused_biter) - [incident:BITES] -> (alleged_victim)
RETURN *

// RDF-like 'fact' context
MATCH (subject) - [verb:PREDICATE] -> (object)
RETURN *