constraint doldur { guard : self.satisfies('IllegalCharactersForName') check { if(self.ownedField.select(f | f.name = "Text").size() <> 1){ var text = new TextField; text.name = "Text"; text.displayName = "Text"; self.ownedField.add(text); } if(self.ownedField.excludes(text)){ return false; } return true; } message : 'laaaa' }