Interactive processing

In contrast to Batch Processing data is entered and processed straight away.

Organisations such as insurance companies are often able to make changes to a customer’s household insurance, for example, while the customer is on the phone. A report of the change would be automatically generated and a copy sent to the customer. Many Building Societies that are offering current accounts process cheques interactively at the till.

Some interactive systems allow queries to be made, but cannot process transactions right away. For example

• Cashpoint machines which allow you to query your balance and withdraw cash but do not update the balance until late at night;
• Point-of-sale terminals which can access a stock file to look up the description and price of an article when the bar-coded label is scanned, but do not alter the quantity in stock when a sale is made. (This is done later in batch mode.)

Pseudo real-time processing

Computer records a transaction and more or less immediately updates the master file (not instantly)

A delay of a few seconds is quite acceptable for selling tomatoes in Sainsbury’s or borrowing a library book, unlike genuine real-time processing. For example

British Airways Booking System, operated by a central computer at Heathrow linked to thousands of British Airways agents in the U.K. and overseas.

A person wanting to book a seat can enquire at any airline office or travel agent about a flight on a particular day, and the booking clerk can call up details on a screen. A booking can be made if a free seat is available, or alternative choices offered.

Such systems need to have methods of ensuring that the same seat is not booked simultaneously by two different agents at different terminals. (This would be a function of a database management system.)

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