9i: Check- constraint Upper(Column)

Hi newsgroup,

Is it possible to build a constraint, that ensures, that there are not more entries in a column, that look like
'Abc ' -> trim(upper(..))='ABC'
'ABC' -> trim(upper(..))='ABC'
'aBC ' -> trim(upper(..))='ABC'

?

Alternativ I could build a shadow column filled by a trigger that containes trim(upper(..)) and a check constraint on this, but it seems to me that there is a better way.

Thank you in advance
Andreas Mosmann

-- 
wenn email, dann AndreasMosmann <bei> web <punkt> de