My recollection is that Oracle supports notifications, which is essentially an event system.
I'm surprised that Postgres has not yet implemented something like this. Would it not make sense to have a notification mechanism integrated into the RDBMS to avoid the necessity of polling ?
Postgres does have notifications. And the article mentions this:
> Notifications are not part of the SQL standard and most relational databases do not support them. There are some exceptions, however. For example, PostgreSQL has very decent support for notifications.
I scanned the documentation TOC and found no mention of them. I guess I would have thought such a fundamental feature would show up in the TOC but it turns out you have to dig into the SQL documentation to find the NOTIFY and LISTEN statements.
If I had used the search feature on the word "notification" I would have found this but it's not necessarily obvious that they would actually be called that (ie. they could be called events or something else).
Oracle has Data Change Notification, which fires a callback when the results of a query change, and AQ which is a pub-sub mechanism that you can invoke from a trigger.
I'm surprised that Postgres has not yet implemented something like this. Would it not make sense to have a notification mechanism integrated into the RDBMS to avoid the necessity of polling ?