#! /usr/bin/perl
use strict;
use warnings;

use DBI;

my %dbargs = (
    PrintError => 0,
);

# mit Umbruch und Leerzeichen
my $dsn1 = qq|DBI:mysql:
    database=pl_test:
    host=localhost:
    port=3306|;

# mit nur 1 Leerzeichen
(my $dsn2 = $dsn1 ) =~ s/\n[\t ]*/ /mg;

# ohne Umbruch oder Leerzeichen
(my $dsn3 = $dsn1 ) =~ s/\n[\t ]*//mg;


# teste alle Varianten
for my $dsn ( $dsn1, $dsn2, $dsn3 ) {

    print "--8<--\n$dsn\n--8<--\n";

    if ( my $dbh = DBI->connect( $dsn, 'user', '', \%dbargs ) ) {

        if ( $dbh->do( q'SELECT * FROM foo' ) ) {
            print "do executed.\n";
        }
        else {
            warn "do failed: ", $dbh->errstr, "\n";
        }

        $dbh->disconnect;
    }
    else { 
        warn "connect failed: ", DBI->errstr, "\n";
        next;
    }
}

__END__

:!perl /tmp/t.pl
--8<--
DBI:mysql:
    database=pl_test:
    host=localhost:
    port=3306
--8<--
do failed: No database selected
--8<--
DBI:mysql: database=pl_test: host=localhost: port=3306
--8<--
do failed: No database selected
--8<--
DBI:mysql:database=pl_test:host=localhost:port=3306
--8<--
do executed.

perl -MDBI -wle 'my $dbh = DBI->connect("DBI:SQLite:\ndbname=data.db",'','') or die "aua"; $dbh->do("SELECT * FROM db_entries");'
DBI connect('
dbname=data.db','',...) failed: unable to open database file at -e line 1
aua at -e line 1.