This is Workflow 1 in the blog tutorial Database activity monitoring and alerting.
Cron node starts the workflow every minute.
Function node generates sensor data (sensor id (preset), a randomly generated value, timestamp, and notification (preset as false) )
Postgres node inserts the data into a Postgres database.
You can create the database for this workflow with the following SQL statement:
CREATE TABLE n8n (id SERIAL, sensor_id VARCHAR, value INT, time_stamp TIMESTAMP, notification BOOLEAN);