Unit 31: File & Data Security

Introduction

Excel worksheets are often used as forms or templates for users to type in their own information and upon which set calculations are then carried out. In such cases, it is important that the user can change only cells where data is to be entered. Excel may also be used for storing data and again it is important to protect this from accidental deletion or amendment. Before you begin exploring how to protect your data, set up this simple worksheet:

  1. Startup Excel (or press ) to get a new workbook

  2. In cell A1, type the instruction: Type your data into cells A3 to A12 – press

  3. Press again then type some numeric data into column A – eg type 1 in A3, press then type 2 into A4; continue until you have 10 in A12 (or use Auto Fill and Fill Series if you like)

  4. Into cell B3 type the formula =a3*a3 then press to remain in cell B3

  5. Now, double click on the small black cell handle to copy the formula down the column to B12

  6. Click on cell B13 then press for [Sum] – press to accept =SUM(B3:B12)

  7. Into cell A14 type Sum of squares: – then press three times

  8. Into cell D14 type the formula =b13 – press

 

Hiding Columns, Rows and Sheets

A very simple way of protecting calculations is to hide them from view:

  1. Right click on the B heading of column B and choose Hide

  2.  Change one of the data values in column A – the sum of squares is recalculated IT Training

  3. Column B has now disappeared and, unless the column is unhidden, exactly what is going on is not immediately obvious. To reshow the column:

  4.  Select columns A and C by dragging through the column headings

  5.  Right click on the selection and choose Unhide

You hide/unhide rows in the same way except you right click on a row number (or selected range of rows).

Tip: If you are unsure as to which columns are hidden (or there are several which are not next to each other) then select all the cells (press once or twice, if necessary) and right click on any column (or row, if rows are hidden) and choose Unhide.

UNIT 31 – File & Data Security


 

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