In the context of computer-based transaction processing systems: –
a. Describe their purpose;
b. Describe two different examples of such systems in differing industries or services;
c. What are the MAJOR security implications of such systems?
d. Describe which of the system development methodologies is most likely to be used, giving reasons for your choice.
a) A transaction is a basic activity conducted at the Operational level of any organization. A computer based transaction processing system (TPS), processes and records the daily routine transactions that any organization must carry out. The criteria and processes are clearly defined, and highly structured. TPS may be operated under batch or on-line conditions.
b) One example of a TPS is a point of sale system (POS) used in supermarkets and other retail stores. This system is used to process sales at the supermarket counters. The inputs for such a system are the type of good and its price. This data is usually encoded in a bar code that is attached on the commodity and swiped past the bar code reader at the POS in order to capture the data. The processing consists of calculating the amount that is due from the customer and also the change that is to be given to the customer once the customer has given money for the commodities. The storage in the system is in the form of a database of files. The records in the files usually describe the commodities on the counter e.g. their name, type, number of units, reorder level, expiration date, etc. The database is updated after each transaction. The output from the POS is a receipt containing details of the purchase of goods the customer such as the goods purchased, their unit cost, the total cost of the purchase, VAT charged, etc.
Another example of a TPS is a flight reservation system. This system is used to book flights of different airlines according to the preferences supplied the client wishing to travel. Inputs for such a system include the date of travel, the time and the preferred airline. The processing consists of checking whether the client preferences can be satisfied and returning a response to the client which will prompt him either to supply different preferences or proceed with the booking paying. The processing also consists of updating the database of records with the details of a client‘s payment. The storage consists of a database containing records of each airline such as the number of flights made in a week, the schedule of the flights, the costs of each flight, etc. The output of such a system is a receipt containing details of the booking.
Other examples of TPSs could include systems in Manufacturing, personnel, academic registration, holiday booking, etc
c) Security implications of transaction processing systems:
o There have to be controls to prevent data capture with errors e.g. repeated data entry
o There have to be controls to ensure that processing is not interrupted for whatever reason e.g. Uninterruptible power supplies could be installed to protect the processing from being interrupted power loss.
o Storage and backup have to be secured from threats to data security e.g. fires, unauthorized access, etc
o Adequate controls in the database have to be put in place to counter security threats, the threat of lost updates, etc
d) As the TPS is crucial to an organization, great care in its design and implementation is essential. Methodologies such as SDLC, SSADM and their variants, with the possible use of prototyping to clearly define the users requirements in their initial stages, are possible candidates for the design and implementation of a TPS. A methodology with rigour and good documentation is required for this system which serves as the foundation to many other management information systems.