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Transactions are events which need to be recorded
with the production, sale and distribution of goods
and services.…read more

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Master files and transaction files
Master file
­ Collection of records holding information about an entity such
as a person or good.
Transaction file
­ Holds information about events occurring in the organisation.
­ For employee payroll file, basically two kinds of transactions:
· Weekly / fortnightly transaction file with information of hours worked ­
used to calculate employees wages or salary.
· Occasional other transactions to process ­ additions, changes and
deletions to the file.…read more

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Batch Processing
Typical, large-scale batch system where data is
collected on paper documents (such as applications for
renewal of a TV or driver's licence) has following stages:
­ The paper documents are collected into batches of say
50, checked, control totals and hash totals calculated
and written on a batch header document.
­ The data is keyed in off-line and validated by a computer
program. It is stored on a transaction file.…read more

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Batch Processing (cont.)
­ Processing begins at a scheduled time ­ maybe
overnight when the computer is not busy dealing
with on-line users. All the processing steps
(beginning with the next) can take place without
operator intervention.
­ Transaction file may be sorted into same
sequence as master file to speed up the
processing of the data.
­ The master file is updated.
­ Any required reports are produced.…read more

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Interactive 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.
­ Some interactive systems allow queries to be made, but
cannot process transactions right away. E.g.…read more

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Real-time & Pseudo real-time
Real-time Processing
­ Computer responds instantly, for example to changes
indicated by sensors and probes in life-support systems
or aircraft control systems.
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.
Example - British Airways Booking System.…read more

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Choice of processing mode
Choice between batch or pseudo real-time depends on:
­ Does information obtained from the system need to be
up-to-date at all times.
­ The scale of the operation - Batch systems well suited to
very high volumes of data, when economical to have an off-
line key-to-disk system for data entry.
­ Cost - Real-time system is generally more expensive
because of more complex backup and recovery procedures
required to cope with power failures or breakdowns.…read more


Mr A Gibson

This clarifies what students often don't have the depth of knowledge on - transaction processing. This provides a decent set of notes on this topic and will help with understanding when creating your own revision materials - e.g. flash cards.

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