my $dbh = DBI->connect(
                  "dbi:Sybase:database=xxx", "user", "pass",
                  { RaiseError => 1 } );

eval {
      my $sth = $dbh->prepare( $sql );
      $sth->execute();
       ...
};

if( $@ ) {
    print STDERR "An error occurred: $@\n";
} else {
    print "All is right\n";
}