Location: [CPSC 333] [Assignments] [More about Problem to Model for Question #1 on Assignment #2]
Question:
While ``clearing'' an account, the system sets the opening date to the current date and applies the registered transactions against the balance, and then deletes these transactions. What about unregistered transactions? Are they also wiped out, or are they just left untouched? If so, then is it okay that in an account there may be unregistered transactions with dates predating the opening date of the account? If this is so, why?
Answer:
The transactions that aren't registered are left ``untouched.'' Yes, it's permissible to have transactions listed that predate the "opening date" for the account.
I would argue that if you didn't change the ``opening date'' when an account is cleared, then this attribute probably wouldn't be of much use at all (unless it had some sort of historical value to the user). As it's described now, it gives some sort of indication of the last time that system information for the account was reconciled with the information on a bank statement for that account, and this might (possibly) be something that a user will want to know.
Since cheques will frequently arrive at the bank and be processed in a different order (sometimes, with the delay between the writing a cheque and its processing differing from cheque to cheque by weeks or months), and since there is a delay between the time when a cheque is written and when it is processed by the bank, it's inevitable that some ``old'' transactions will be left around, after an account has been cleared. Given the way that I've said that the ``opening date'' should be changed, this will mean that these transactions will have dates that precede the new ``opening date'' for the account.
Now, this attribute was probably poorly named; maybe ``opening or balancing date'' would have been more accurate. However, I'll ask you to use the name for the attribute that's been given on the problem description, ERD, and data dictionary, with the understanding that it'll be used as described above.