Types of Processing of Data

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• There are different types of processing:

• batch

• interactive

• transaction.

• Characteristics of each type.

• Appropriate contexts for their use.

Processing• Data may be processed in different ways

according to what is most suitable.• Types:

– Batch,– Pseudo real time,– Real time,– Interactive,– Transaction,– On-Line.

Transactions

• Transactions are recorded events that happen everyday in the process of selling and purchasing goods and services.

• Transactions usually refer to money, cashing a cheque at a bank is a transaction.

• Transactions can refer to other activities, such as:– Taking out a library book,– Applying for a driving licence,– Taking the school register.

Files• Master File:

– A collection of records holding information on a group of people or objects.

– Each record will hold multiple fields of data.– Some fields will change regularly, some often and

some seldom.

• Transaction File:– A file holding information on events or things that

change, some will be regular events, and some will be additions, updates or deletions.

• Changes are recorded on the Transaction files, and when finished are transferred to the Master file in a single process.

Files

• An employee holds a master file and transaction files for his employees.

• What would some records be in the master file?

• What files may be held as transactions?• What would be regular transactions?• What would be add, update and delete

transactions?

Batch Processing

• A large collection of similar transactions are put together over a period of time and then processed in one go.

• This means that the processing is done at a convenient time for the operators or when the computers are less busy.

• What could be an example of batch processing?

• Some systems are not suitable for batch processing, – i.e. a flight control system…why?

How does Batch Processing Work?

• Take for example a home order sales business.• Order applications are received by telephone, or

by the Internet, or through the post, and transferred to data capture forms ready for processing.

• The data capture forms will be collected until there are enough to do a batch process. These documents will be checked, control totals and batch headers will be added.

• Data from the data capture forms will be entered into a database known as the transaction file.

• The data will be validated by the computer software to check that the data is reasonable.

• What does reasonable mean?• The data will also be verified, this is done by

using another operator to key in the same data.• How does the computer verify data? • Any errors found can be corrected, and re-input.• The process of transfer from transaction file to

master file is normally done at a time when the computers are at their least busiest, e.g. over-night.

• This process usually does not need an operator after first being set up.

• After the master file has been updated, reports are printed off for management.

Real Time Processing

• This is an instantaneous recording on the file or database of an event.

• Computers need to respond instantly to data that is received.

• A nuclear reactor will have many sensors feeding back information constantly to a computer, all of these readings are checked against safety limits.

• Any data received outside will set off another set of instructions to control any safety devices.

• A delay of even a few seconds may result in injury or death to the operators.

Pseudo Real Time Processing

• This is a near instantaneous recording on a file or database.

• The computers need to respond to an event but it need not be instantaneously.

• An airline booking system needs to be updated every time a flight is booked, to avoid two people being booked onto one seat, but a delay of a few seconds to a minute will not affect this as the transaction will always take place (system programmed) before the next booking.

• Customers can enquire whether seats are available and the operator can look up the database to see what seats are still available.

Interactive Processing

• Known as On-Line processing as any file may need to be accessed immediately, - files are on disk not stored somewhere else.

• Data is entered and processed into the system in one stage.

• Queries and orders may be made over the telephone and Internet, confirmation is given and the stock database is amended in one step.

• A customer invoice is produced, a copy goes to the warehouse for despatch.

What Mode of Processing?

• Does the information output need to be completely up to date at all times?

• Is there very high volumes of data that would use up computer time?

• Can spare computer capacity be used overnight?

• Expensive backup and recovery procedures for a real time procedure.

• Can a combination of both be used?