What's the best way for the client app to immediately react to an update in the database?

Question

What is the best way to program an immediate reaction to an update to data in a database?

The simplest method I could think of offhand is a thread that checks the databa

Answer 1

Unfortunately there's no way to push data to a web browser - you can only ever send data as a response to a request - that's just the way HTTP works.

AJAX is what you want to use though: calling a web service once a second isn't excessive, provided you design the web service to ensure it receives a small amount of data, sends a small amount back, and can run very quickly to generate that response.