sub foo {
  my $o  = {  q{debug}  => 0,           ## debug 0|1.
              q{db}     => SQL_DB,      ## sql db.
              q{host}   => SQL_SERVER,  ## sql server.
              q{port}   => SQL_PORT,    ## sql server port.
              q{user}   => SQL_USER,    ## sql user.
              q{pass}   => SQL_PASS,    ## sql user pass.
              @_
            };

  ## do your safety checks...

  my $dsn = q{DBI:mysql:database=} . $o->{'db'} .
            q{;host=} . $o->{'host'} .
            q{;port=} . $o->{'port'};

  my $objSQL = eval {
    DBI->connect( $dsn,
                  $o->{'user'},
                  $o->{'pass'},
                  { 'PrintError'  => 0,
                    'RaiseError'  => 0 } );
  };
  if ( ( $@ ) || ( ! defined $objSQL ) ) {
    ## maybe we only want to show the error if in debug??
    print STDERR $DBI::errstr if ( $o->{'debug'} );
    return undef;
  }

  DBI->install_driver( q{mysql} );
  return $objSQL;
}