Data Validation rules enable you, as the owner of the workbook, to set rules on what entries are allowed inside individual cells.
For instance, you can set one Validation Rule that only allows whole numbers between 1 and 100 to be entered into a cell. And, on another cell in the same workbook, you can specify that only entries from a drop-down list that you’ve created can be entered into a cell.
Setting Data Validation Rules
Select the cells on which you want to enable Data Validation
Choose Data: Validation… from the Menu bar
Figure 16. Data Validation Dialog Box - Settings Tab
3. On the Settings tab, choose the value type that you will allow
4. Click the Input Message tab
Figure 17. Data Validation Dialog Box - Input Message Tab
5. Enter the Title and Message to help your user understand what is required for input
6. Click the Error Alert tab
Figure 18. Data Validation Dialog Box - Error Alert tab
7. Set your error message Style, Title and Message
8. Click OK
Remove Data Validation Rules
Once Data Validation is set, it’s actually very easy to remove.
Select the cells on which you want to disable Data Validation
Choose Data: Validation…
Click Clear All