as we can see in http://www.sqlite.org/lang_expr.html, Upper instruction doesn't converts accents (`,´) and other UTF8 characters to Upper.
If we have a this table:
When we try a select like
"select count nombre from pepe where upper(nombre)='CORTÉS'"
it does not work.
If you need to compare those values, you could try with LOWER instruction (Lower works fine!).