My sql dialect to sql type text

== About varchar(N) type in MySQL ==
N is number of characters.
A varchar column can store up to 65535 bytes.
Remember that 1 character is more than 1 bytes. (i.e. 3 bytes in utf-8 charset.)
Also remember that each row can store up to 65535 bytes, and you have some overheads, so it's not possible for a varchar column to have 65535/3 characters (in case of utf-8) really.
So it would be better to use 'text' type in stead of large varchar type.