31 lines
1.4 KiB
Plaintext
31 lines
1.4 KiB
Plaintext
ID: credit promise debt
|
|
--------------------------------
|
|
Club: 0 +7200 -23450
|
|
john: 7200 +0 -7200
|
|
# Reflect john paying its bills all at once ...
|
|
Club: 7200 +0 -23450
|
|
john: 0 +0 0
|
|
# Charge Club with server hosting provided by alex ...
|
|
Club: 0 +0 -16250
|
|
alex: 7200 +16250 0
|
|
# Some updates and deletes that could, unless denied, destroy consistency ...
|
|
Error: near line 300: paid is set and adjusted automatically according to added Transfer records
|
|
Error: near line 301: Debt is involved in transfers to revoke at first
|
|
Error: near line 302: FOREIGN KEY constraint failed
|
|
# After revoking transactions, you are free to change or delete debts and credits ...
|
|
Club: 7200 +0 0
|
|
alex: 0 +0 0
|
|
# But let's rollback that what-if excurse. This is how it currently is ...
|
|
Club: 0 +0 -16250
|
|
alex: 7200 +16250 0
|
|
###################################################################
|
|
# Now it is your turn: Study the sql code yielding the output above
|
|
# then enter new members and let them pay the fees.
|
|
# (PLUS: Let have one discalculia and pay too little or too much.)
|
|
# Once the club has enough money to pay alex' hosting service,
|
|
# update (i.e. revoke and reenter) the respective transaction.
|
|
# Finally issue a bank transfer to alex. Hint: An outgoing transfer
|
|
# is simply a debt charging alex' own virtual account and without
|
|
# targetCredit (NULL). PLUS: What happens if the description of
|
|
# the bank transfer does not contain any or only a wrong IBAN?
|