2.4. CREATE NOTIFICATION¶
CREATE NOTIFICATION
tells the tesseract server to publish changes to the
Redis pub/sub model.
2.4.1. Syntax¶
CREATE NOTIFICATION <notification_name>
ON <table_name>
[ WHERE <where_clause> ]
- notification_name
- The name of the notification must be unique and non-existent. It follows the same rules as naming an entity like a table.
- table_name
- The table to watch for changes.
- where_clause
Any expression which will cause the notification to fire only if it evaluates to
true
:CREATE NOTIFICATION bobs ON people WHERE first_name = 'Bob';
2.4.2. Notes¶
Multiple notifications can be fired for a single insert but is limited to one
notification per NOTIFICATION
defined.
Notification use the Redis PUB/SUB model, so when the actual notification is fired it is sent as a publish through Redis. Your notification name is the channel that the message will be published to.
This means that software does not need to know anything about the tesseract server if they only intent to subscribe. Published notifications are the complete JSON record.