Assuming your update statement is correct, given your database structure and Oracle (I'm more familiar with mySQL):
use DBI;
use strict;
my $user = 'user';
my $pass = 'pass';
my $db = 'database';
my $filename = 'filename.txt';
my $query = qq*
update
(
select t1.field1, 999 deact_status
from
schema.table1 t1
inner join schema.table2 t2 on t1.id = t2.id
where
t2.field2 = ?
)
set
field1 = deact_status
*;
my ($dbh, $sth, $handle);
$dbh = DBI->connect("dbi:Oracle:$db", $user, $pass)
|| die "Couldn't connect to database: " . DBI->errstr;
open ($handle, $filename)
|| die "Couldn't open $filename for read.\n";
while (<$handle>) {
chomp;
$sth = $dbh->prepare_cached($query, {}, 1);
$sth->execute($_);
}
$dbh->disconnect();
This is untested, but ought to work in theory.