1. Data Verification and Validation

2. Learning objectives At the end of the lesson you will: -
Know what data verification is
Know what data validation is
Create a validation rule in a database table

3. What is Data Verification?
Data verification is checking the data.
You must: -
Check for spelling mistakes.
Check for data that has not been entered correctly.
Check that all data has been entered and nothing is missing.

4. Why do you Check the data?
We all make mistakes and so its important to check.
Data Verification
Incorrect data can lead to problems, such as letters being sent to the wrong address

5. How can you check it? Reading through your records. Spell check.
Compare your data entry sheet with the data table on your computer.
Entering the data twice i.e. creating a new password.

6. What is Data Validation?
The computer checks the data you enter.
The computer checks if the data is correct and makes sense.

7. Data Type

8. How?
List menu
Create a validation rule
Input mask

9. Validation types
Format check – e.g. two letters followed by two numbers – PR15 would be valid but PRX71 would not.
Presence check – checking that the field contains any data.
Range check –checking that the data is between certain numbers or letters, e.g. A–E.
Lookup check – checking that only values from a set list can be entered, e.g. M or F.
Size check – checking data falls within a minimum or maximum number of characters.

10. Validation and Verification
Summary

11. Verification Is done by the user
By entering the data twice and comparing the values entered is a form of verification.
Verifying that there are no spelling mistakes
Correct data is entered - ie correct name, address, postcode

12. Validation Is checked by software
Is it the correct data type – date of birth in a currency field
Would not pick up spelling mistakes
Would not detect incorrect data of the same data type being entered