apoc.refactor.extractNode

Details
Syntax	`apoc.refactor.extractNode(rels, labels, outType, inType) :: (input, output, error)`
Description	Expands the given `RELATIONSHIP` VALUES into intermediate `NODE` VALUES. The intermediate `NODE` values are connected by the given `outType` and `inType`.
Input arguments	Name	Type	Description
	`rels`	`ANY`	The relationships to turn into new nodes. Relationships can be of type `STRING` (elementId()), `INTEGER` (id()), `RELATIONSHIP`, or `LIST<STRING \| INTEGER \| RELATIONSHIP>`.
	`labels`	`LIST<STRING>`	The labels to be added to the new nodes.
	`outType`	`STRING`	The type of the outgoing relationship.
	`inType`	`STRING`	The type of the ingoing relationship.
Return arguments	Name	Type	Description
	`input`	`INTEGER`	The internal id of the original entity.
	`output`	`NODE`	The copied entity.
	`error`	`STRING`	Any error that occurred during the copy process.

Refactoring nodes using Cypher

Node labels and relationship types can be referenced dynamically in Cypher without using APOC.

Cypher syntax for creating, matching and merging labels and types dynamically

CREATE (n1:$(label))-[r:$(type)]->(n2:$(label))
MERGE (n1:$(label))-[r:$(type)]->(n2:$(label))
MATCH (n1:$(label))-[r:$(type)]->(n2:$(label))

The dynamically calculated type must evaluate to a STRING or LIST<STRING>. For more information, see the Cypher Manual → CREATE, MERGE, MATCH.

Usage Examples

The examples in this section are based on the following sample graph:

CREATE (origin:Airport {code: "LHR"})
CREATE (destination:Airport {code: "AMS"})
CREATE (origin)-[:FLIGHT {number: "BA001"}]->(destination);

The following creates a Flight node with an IN relationship from LHR and an OUT relationship to AMS:

apoc.refactor.extractNode

MATCH (:Airport)-[rel:FLIGHT]->(:Airport)
WITH collect(rel) AS rels
CALL apoc.refactor.extractNode(rels,['Flight'],'OUT','IN')
YIELD input, output
RETURN input, output;

Using Cypher

MATCH (:Airport)-[rel:FLIGHT]->(:Airport)
CALL (rel) {
    WITH startNode(rel) AS startNode, endNode(rel) AS endNode, rel
    CREATE (startNode)-[:IN]->(f:Flight)-[:OUT]->(endNode)
    SET f = properties(rel)
    DELETE rel
}
RETURN 0 AS input, newNode AS output

Results
input	output
0	(:Flight {number: "BA001"})

We can list all the Flight nodes by running the following query:

MATCH path = (origin)-[:IN]->(:Flight)-[:OUT]->(destination)
RETURN path;

Results
path
(:Airport {code: "LHR"})-[:IN]→(:Flight {number: "BA001"})-[:OUT]→(:Airport {code: "AMS"})