Having two widgets connected to each other you might get this error: illegal mix of collations.

In mysql there is a way to configure each field with a different char set but you can't query both together.

Here is a link explaining how to solve this issue:
http://www.notoriouswebmaster.com/selected-notes-on-web-tech/colliding-collations-in-mysql/

And one from mysql.com:
http://dev.mysql.com/doc/refman/5.0/en/charset-general.html