In newer versions of DBI the connect call has changed (the old one still works, but is depreceated). The call should be:

my $dbh = DBI->connect("dbi:mysql:foo", "bar", "baz",
      { AutoCommit => 1, RaiseError => 1})
        or die die "Can't connect: ", $DBI::errstr;
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Where the "dbi:mysql:foo" bit is "dbi:'DBD-driver-name':'database-name-and-options'".
You will have to see in the documentation for your chosen DBD to see what is possible and legal for the 'database-name-and-options' part.

RaiseError is set in an anonymous hash - along with other database attributes.

Note that I set AutoCommit state in the connect call. This is highly recommended, and will become mandatory in a coming DBI release.
The reason is that the ODBC spec (which DBI follows as closely as possible) has AutoCommit=>1 as default, while many (most?) major database systems have AutoCommit=>0 as default. This has lead to much confusion and tearing of hairs in the past, as things were commited unintentionally.