[newbie] How to do "batch insert"?

Hi all.
In the scene I want to insert all elements of an array in to a
table, how can I do to commit them as a whole?
currently I do like this:

<?php
$result = pg_prepare($dbconn, "ins_acl", 'INSERT INTO
acls(oid,uid,gid,mod) VALUES($1,$2,$3,$4)');
for($i=0;$i<count($p["acls"]);$i++){
pg_execute($dbconn, "ins_lgs",$p["acls"][i]);
}
?>

I wonder while doing so, will it commit in each LOOP or just ONCE?

Thanks and Regards,

Ian