PHP: Check mysql database every 10 seconds for any new rows

Question

I am making a php chat and am starting the php checking database part. So when a user types something into the chat, it gets recorded in the MySQL database, how would I chec

Answer 1

PHP doesn't have a setInterval function. While I'm sure you can use a crontask to automate it on the server, you can also achieve this with some simple Javascript.

The concept you are trying to achieve is known as Short Polling. What you want to do is to have a setInterval function in Javascript that constantly makes AJAX requests to your PHP file which performs the check to the database for new messages. Your PHP should return that information to your script where you can then simply populate the user's screen.

There is also Long Polling where you simply maintain the connection and have a setTimeout to wait for messages to come in. You can find more information yourself and if you have questions, you can come back here.

A good video about this:

https://www.youtube.com/watch?v=wHmSqFor1HU

Hope this helps.