apoc.nodes.link

Procedure APOC Core

apoc.nodes.link([nodes],'REL_TYPE', conf) - creates a linked list of nodes from first to last

Signature

apoc.nodes.link(nodes :: LIST? OF NODE?, type :: STRING?, config = {} :: MAP?) :: VOID

Input parameters

Name	Type	Default
nodes	LIST? OF NODE?	null
type	STRING?	null
config	MAP?	{}

Name

Type

Default

nodes

LIST? OF NODE?

null

type

STRING?

null

config

MAP?

{}

Config parameters

This procedure supports the following config parameters:

Table 1. Config parameters
name	type	default	description
avoidDuplicates	boolean	false	If true, the relationship will not be created, if it already exists

Usage Examples

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

CREATE (:Event {name: "Event 1", date: datetime("2019-06-01")})
CREATE (:Event {name: "Event 2", date: datetime("2019-06-04")})
CREATE (:Event {name: "Event 3", date: datetime("2019-06-08")});

We can create a linked list of these events, by running the following query:

MATCH (e:Event)
WITH e ORDER BY e.date
WITH collect(e) AS events
CALL apoc.nodes.link(events, "NEXT")
RETURN count(*);

We can check for relationship existence using the {avoidDuplicates: true} configuration; calling the previous query twice, 2 relations of type "NEXT" will be created between the nodes, instead, by executing CALL apoc.nodes.link(events, "NEXT", {avoidDuplicates: true}) only one relationship of type "NEXT" will be created.