Что не хватает?
<?php
$DB_HOST = "localhost";
$DB_USERNAME = "root";
$DB_PASSWORD = "1234567";
$DB_NAME = "ALL";
$LOCAL_DUMP_PATH = "C:\AppServ\MySQL\bin\\";
$FILENAME_PREFFIX = "sqldump";
$filename = $FILENAME_PREFFIX.date("YmdHis").".sql";
$dump_cmd = "mysqldump -h $DB_HOST -u $DB_USERNAME -p $DB_PASSWORD";
if ($DB_NAME == "all" || $DB_NAME = "ALL")
{
$dump_cmd .= " --all-databases";
}
else
{
$dump_cmd .= " $DB_NAME";
}
$dump_cmd .= " > $LOCAL_DUMP_PATH"."$filename";
system($dump_cmd);
echo "Done.";
?>