apoc.trigger.add

This procedure is not intended to be used in a cluster environment, and may act unpredictably.

Please note that this procedure is deprecated.

Use the following ones instead, which allow for better support in a cluster:

deprecated procedure

new procedure

apoc.trigger.add(name STRING, statement STRING, selector MAP<STRING, ANY>, config MAP<STRING, ANY>)

apoc.trigger.install(databaseName STRING, name STRING, statement STRING, selector MAP<STRING, ANY>, config MAP<STRING, ANY>)

apoc.trigger.remove(name STRING)

apoc.trigger.drop(databaseName STRING, name STRING)

apoc.trigger.removeAll()

apoc.trigger.dropAll(databaseName STRING)

apoc.trigger.pause(name STRING)

apoc.trigger.stop(databaseName STRING, name STRING)

apoc.trigger.resume(name STRING)

apoc.trigger.start(databaseName STRING, name STRING)

where databaseName is the database where we want to execute the triggers.

Details
Syntax	`apoc.trigger.add(name, statement, selector [, config ]) :: (name, query, selector, params, installed, paused)`
Description	Adds a trigger to the given Cypher statement. The selector for this procedure is {phase:'before/after/rollback/afterAsync'}.
Input arguments	Name	Type	Description
	`name`	`STRING`	The name of the trigger to add.
	`statement`	`STRING`	The query to run when triggered.
	`selector`	`MAP`	`{ phase = "before" :: ["before", "rollback", "after", "afterAsync"] }`
	`config`	`MAP`	The parameters for the given Cypher statement. The default is: `{}`.
Return arguments	Name	Type	Description
	`name`	`STRING`	The name of the trigger.
	`query`	`STRING`	The query belonging to the trigger.
	`selector`	`MAP`	`{ phase = "before" :: ["before", "rollback", "after", "afterAsync"] }`
	`params`	`MAP`	The parameters for the given Cypher statement.
	`installed`	`BOOLEAN`	Whether or not the trigger was installed.
	`paused`	`BOOLEAN`	Whether or not the trigger was paused.

Enable Triggers

By default triggers are disabled. We can enable them by setting the following property in apoc.conf:

apoc.conf

apoc.trigger.enabled=true
apoc.trigger.refresh=60000

Description
Option Key	Value	Description
apoc.trigger.enabled	true/false, default false	Enable/Disable the feature
apoc.trigger.refresh	number, default 60000	Interval in ms after which a replication check is triggered across all cluster nodes

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

CREATE (:Counter {count:0})
CREATE (f:Foo);

Let’s create a trigger that keeps a count of the number of nodes that have been deleted:

CALL apoc.trigger.add(
  'count-removals',
  'MATCH (c:Counter)
   SET c.count = c.count + size([f IN $deletedNodes WHERE id(f) > 0])',
  {}
);

Results
name	query	selector	params	installed	paused
"count-removals"	MATCH (c:Counter) SET c.count = c.count + size([f IN $deletedNodes WHERE id(f) 0])	{}	{}	TRUE	FALSE

We’ll now delete the Foo node:

MATCH (f:Foo)
DELETE f;

Results

0 rows available after 20 ms, consumed after another 0 ms
Deleted 1 nodes

And finally, let’s check that the count property on our Counter node has been incremented:

MATCH (c:Counter)
RETURN c.count as count;

Results
count
1