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Implementation and System Security

Data conversion

  • 3 things to know
  • AS Unit 1

Overview

Data conversion, two ways in which data can be converted and data cleansing.

What you need to know

Answer each one before you reveal it.

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Key term

Why is data conversion needed even when both systems are computerised?

Key term

Give one drawback of converting data by manual re-entry.

Key term

Why is data cleansed before transfer rather than afterwards?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    What is data conversion?

    Model answer

    Data conversion is the work of taking the data held by the old system and putting it into the form and the structure the new system requires.

  2. 2

    Why is data conversion needed even when both systems are computerised?

    Model answer

    Two systems rarely store data in the same way, so field names, data types, code values and file formats must all be translated before the new system can use the old records.

  3. 3

    Describe two ways in which data can be converted.

    Model answer

    Data can be converted by writing a program that reads the old files and writes them out in the new format, or by keying the records in by hand where no usable electronic copy exists.

  4. 4

    Give one drawback of converting data by manual re-entry.

    Model answer

    Manual re-entry is slow and introduces typing errors, so a large volume of records takes a long time and arrives in the new system less accurate than it was before.

  5. 5

    What is data cleansing?

    Model answer

    Data cleansing is the correction of existing records before they are transferred, removing duplicates, filling gaps and putting inconsistent entries into one agreed form.

  6. 6

    Why is data cleansed before transfer rather than afterwards?

    Model answer

    Faulty records loaded into the new system spread through its reports and calculations at once, and cleaning them in place afterwards is far harder than cleaning the extract first.

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