I'm not familiar with the qw(:sql_types) part. ... I didn't see a sql_types subroutine in the documentation for DBI 1.13.

It was added in 0.88, so I believe you should have it. It imports sql type constants such as 'SQL_VARCHAR'. You can see what it imports with this (which is straight from the DBI docs):

foreach (@{ $DBI::EXPORT_TAGS{sql_types} }) {
  printf "%s=%d\n", $_, &{"DBI::$_"};
}
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