my $DB;
my @DB = qw(DB1 DB2);

&select_db();
if (!$DB) {&select_db();}
if ($DB eq 'Q') {die;}

sub select_db {
print "Select a database: ";
  $DB = <STDIN>;
  for (@DB) {
    if ($DB =~ /$_/i) {
       return $DB;
    }
  }
}