multiple parameters in if statement

[Kun]

I am trying to make an if-statement that will not do anything and print 
'nothing entered' if there is nothing entered in a form.  I have the 
following code that does that, however, now even if I enter something 
into the form, the code still outputs 'nothing entered'.  This violates 
the if statement and I am wondering what I did wrong.

     if form.has_key("delete_id") and form["delete_id"].value != "" and 
form.has_key("delete_date") and form["delete_date"].value != "" and 
form.has_key("delete_purchasetype") and 
form["delete_purchasetype"].value != "" and form.has_key("delete_price") 
and form["delete_price"].value != "" and form.has_key("delete_comment") 
and form["delete_comment"].value != "":
         delete_id=form['delete_id'].value
         delete_date=form['delete_date'].value
         delete_purchasetype=form['delete_purchasetype'].value
         delete_price=form['delete_price'].value
         delete_comment=form['delete_comment'].value
     else:
         print "ERROR: Nothing entered!"
         raise Exception