牧羊人

A BLOB is a binary large object that can hold a variable amount of data. The four BLOB types are TINYBLOB, BLOB, MEDIUMBLOB, and LONGBLOB. These differ only in the maximum length of the values they can hold.

BLOB columns are treated as binary strings (byte strings). TEXT columns are treated as non-binary strings (character strings). BLOB columns have no character set, and sorting and comparison are based on the numeric values of the bytes in column values. TEXT columns have a character set, and values are sorted and compared based on the collation of the character set.

http://www.icewalkers.com/Perl/5.8.0/lib/DBI/FAQ.html#5.2%20How%20do%20I%20handle%20BLOB%20data%20with%20DBI%3f 

5.2 How do I handle BLOB data with DBI?
XX