apoc.trigger.show

Details
Syntax	`apoc.trigger.show(databaseName) :: (name, query, selector, params, installed, paused)`
Description	Lists all eventually installed triggers for a database.
Input arguments	Name	Type	Description
Input arguments	`databaseName`	`STRING`	The name of the database to show triggers on.
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

Usage Examples

The apoc.trigger.* procedures are intended to be executed in the system database, therefore they have to be executed by opening a system database session.

There are several ways of doing this:

When using Cypher-shell or Neo4j Browser, prefix Cypher queries with :use system
When using Fabric, prefix Cypher queries with USE system
When using the drivers, open a session directly against the system database

Moreover, the apoc.trigger procedures accept as first parameter the name of the database in which the triggers should be installed, updated, or removed.

Installing, updating, or removing a trigger is an eventually consistent operation. Therefore, they are not immediately added/updated/removed, but have a refresh rate handled by the APOC configuration apoc.trigger.refresh=<MILLISECONDS>, with default 60000 (milliseconds).

This example assumes that an apoc.trigger.install has already been executed:

CALL apoc.trigger.show('neo4j');

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