Insert data into two database without lose data.

Hi ,
I have two database with MyIsam Engine :
db1 : usersys1
db2 : usersys2

when user register on my site i will Insert all user info to both db separately in last register step.
how it possible to be sure we will don't miss one of this Inserts ? (for example db1 ok , db2 insert failure due to anything)

I need to insert all data to both database %100.

for example maybe one of databases have problem or user connection closed
before full insert.

 

$query = 'MYSQL_QUERY';

$first_data = mysql_query($query, data1);
if($first_data){
     $second_data = mysql_query($query, data2);
     if($second_data){ echo 'inserted both';}else{ echo 'unable to insert to second one';}
} else {
     echo 'unable to insert to both databases.';
}

PHP:

Peace,

 

maybe db2 result is failure , can we use rollback or such things for db1 ?
can we use commit in mysql 5 for MyIsam engine? if yes , how to use?

 

I googled mysql php transactions and came up with this: http://www.devarticles.com/c/a/MySQL/Using-Transactions-with-MySQL-4.0-and-PHP/
You can easily adapt the last PHP script on that page to use 2 mysql connections. If, at some point one of the queries fails (either databases), call the rollback function created there (for both dbs).