Auto refresh based on DB modify

[jasonyoung]

This scenario involves 3 PC's.
PC #1 is the Order Supervisor, charged with updating the DB.
PC #2 is the PC displaying the table echoing out the query results to a wall mount plasma.
PC #3 is the PHP/Apache/MySQL server.

PC #1 user will be updating the DB with open orders as they come in and clearing the open orders as they are completed. Simple stuff so far.

What I want is for PC #2 to refresh everytime PC #1 posts an update to MySQL. My thinking is instead of just doing an auto-refresh on PC #2 every 10 seconds (unnecessarily hammering SQL) to only refresh if the DB gets modified. The tricky part is how do I initiate the refresh on PC #2 when the DB gets modified? (Nobody sits at PC #2)

Can this be done? I don't see how to tell PC #2 about the update... but you guys are pretty smart... Can you help out?

Much thanks.

[Roger_Ramjet]

If you set up query cache then the server will only be requeried when the underlying data has been updated, otherwise the cached results are returned so you will not be hammering the server.

Up to you how you handle the page refresh. You might want to look into AJAX as a means to check for updates instead of reloading the whole page. Also, page expires and las modified could be used to trigger reloads.