Why are transactions collected into a file rather than applied immediately?

A batch run lets the master file be updated in one efficient sequential pass. Processing can also be scheduled overnight when the system is otherwise idle.

What are the three usual types of transaction?

The three types are insertion of a new record, amendment of an existing record and deletion. Each transaction record carries a code saying which type it is.

Which file is sorted before a batch update, and why?

The transaction file is sorted into the same key order as the master file. The two files can then be read in one pass without going backwards.

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Files, Records and File Organisation

Master files and transaction files

3 things to know
Component 2

Overview

Master file, transaction file and transaction record in a stock control system.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What is a master file?

Key term

What is a transaction file?

Key term

Give an example of a transaction record in a stock control system.

Questions from this subtopic

Each one with the model answer underneath.

1
What is a master file?
Model answer
A master file is the permanent file holding the main data of a system. Customer accounts and stock levels are typical master file contents.
2
What is a transaction file?
Model answer
A transaction file is a temporary file of the changes collected since the last update. The changes are applied to the master file in one batch run.
3
Give an example of a transaction record in a stock control system.
Model answer
A transaction record might show that 20 units of product 4471 were sold today. The record holds a key, a transaction type and a quantity.
4
Why are transactions collected into a file rather than applied immediately?
Model answer
A batch run lets the master file be updated in one efficient sequential pass. Processing can also be scheduled overnight when the system is otherwise idle.
5
What are the three usual types of transaction?
Model answer
The three types are insertion of a new record, amendment of an existing record and deletion. Each transaction record carries a code saying which type it is.
6
Which file is sorted before a batch update, and why?
Model answer
The transaction file is sorted into the same key order as the master file. The two files can then be read in one pass without going backwards.

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