my $dbname   = 'production';
my $username = 'code_monkey';
my $password = '!#@&*';

# You can also specify the database here instead of using the '$dbh->do("use $dbname");'
my $dbh_foo = DBI->connect("dbi:Sybase:server=Foo;database=$dbname",$username,$password );

# Here you can call a second one
my $dbh_bar = DBI->connect("dbi:Sybase:server=Bar;database=$dbname",$username,$password );

# You can even call a completely different RDBMS
my $dbh_baz = DBI->connect("dbi:Pg:host=baz;dbname=$dbname",$username,$password );