Listing 5 DBI code example

use DBI;

$ENV{ORACLE_HOME} = '/opt/oracle/product/8.1.7';
my $dbuser = 'db_username';
my $dbpass = 'db_password';
my @db = qw( instance1 );

foreach my $db (@db) {
    my $result = check_db($db);
    if($result) {
        foreach (@$result) {
            if ( @$_[0] =~ /^\bOPEN\b$/ ) {
                debug($db,'OK');
            } else {
                debug($db,'DOWN');
                logit("ORACLE $db down, monitor should be true");
                exit 0;
            }
        }
    } else {
        logit("ORACLE $db down, but should be true");
        exit 0;
    }
}

sub check_db {
    my ($db) = shift;
    my ($dbh) = DBI->connect("dbi:Oracle:$db", $dbuser, $dbpass, {
            RaiseError => 0,
            AutoCommit => 1,
            PrintError => 0 });

    unless ( $dbh ) {
        warn "Could not connect to $db: $DBI::errstr\n";
        return 0;
    }

    my $sth = $dbh->prepare("select status from v\$instance");
    $sth->execute;
    my $row = $sth->fetchall_arrayref;
    $sth->finish;
    $dbh->disconnect;
    return $row;
}