Automatic time updating?

[3raser]

Hey!

 

I've always wondered about this, and I've always thought this would become handy if I ever wanted to create a big website. How do I make it so after 24 hours, their be a change in the database? Example of what I mean:

 

You vote for something, and you must wait 24 hours before voting again. You visit the next day, 24 hours+, and it lets you vote.

 

How would I make something like this?

[andrewgauger]

Put a timestamp in the table (default to NOW) and compare the values before updating.

[3raser]

Put a timestamp in the table (default to NOW) and compare the values before updating.

 

Understandable. But how would I compare them?

[andrewgauger]

Well a timestamp is simply the number of seconds since (appx) 1970.  So if you take the value stored in the database and add 86400 to it, you can then:

 

$result=mysql_fetch_array(mysql_query("SELECT time FROM table_name WHERE condition")));
if ($result[0]+86400 < time()){
//todo: write the code that is acceptable after 24 hours
}

[Ken2k7]

Example:

SELECT COUNT(*) c FROM table WHERE DATE_SUB(CURDATE(), INTERVAL 1 DAY) <= timestamp_column AND userid = 1;

 

Take a look here - http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html

 

It has tons of useful functions for you to pick at.