How does DBD::Oracle handle NULL values?

NULL values are treated as the value "undef" in DBI. Use one of the following methods to insert NULLs into an Oracle database:

$rc = $dbh->do("INSERT INTO tableName VALUES(SYDDATE, NULL)");

or...

$sth = $dbh->prepare(qq{ INSERT INTO tableName VALUES (?, ?) });
$sth->execute("10-JUN-2005", undef);

When queried, NULLs should be tested against undef. Example:

if (!defined $var) { ...