invalidate entry in memcache using php

[p23]

Hi, I'm very beginner to memcached and php

How do i invalidate items in memcache after the database has been
written?
I put these query to mysql to read:

“SELECT * FROM employees"
so will retrieve it from database and cache it using a key.
Let say it will gives result of 10 records.

After a while i insert a new record with id=x
So, how do i invalidate this query that was cached recently?
Thus, if a user invoke this query again, it will return new result
with 11 records.

[Henrik Schröder]

http://dk2.php.net/manual/en/memcached.delete.php