I work for New York City Fire Department. We are attempting to create a dashboard of open incidents. We want the vendor to query the table of incidents stored in our Oracle instance (currently hosted on a Windows box but soon migrating to exadata). They can run their query at some regular interval, but the most efficient method is for them to be informed when a new incident has been inserted into the incident table, or when an incident is closed (Incident_close_datetime transitions from "null" to "not null"). I recently read a discussion about running a shell script from a trigger and even though there was a solution posted, one expert admonished against using this method. My question is: What features are provide by Oracle to enable notification to an external application when an insert occurs or a field is update?