Not sure what would cause that. I don't use Sybase, but I've used Oracle, MySQL, and Postgres, and their respective DBD's, and I haven't seen that in any of those. The "Programming ther Perl DBI" book doesn't give any clues in the DBD::Sybase section towards the back - in fact it says that LongReadLen and LongTruncOk attributes aren't even supported. It also says that CHAR, VARCHAR, BINARY, and VARBINARY are all limited to 255 chars in length. Of course, that book is a few years old :-)

If you don't get any answers here, try asking on the DBI mailing list - there are at least a few Sybase people on that list, including Michael Peppler who is the author of the DBD::Sybase module.

HTH.