AS Computing Verification

Once sensible data has been entered, the second of method of ensuing data integrity can be employed. Verification is the process of checking that the sensible data entered is actually the data you want. For example, you have a field called NAME, you enter JANS. This is valid data., but when you double check it, you realise that it should be JANES. You can then correct it. This is verification.

Re-type a value This is commonly used when you set up or change a password. You type in your password once and then you it in a second time. If they both match, then your password is accepted. If they do not match, even though both entries are valid, then it is rejected and you are asked to try again.

Re-enter whole data files This is used in data processing environments. Operator A types in a set of paper-based orders. They are saved in a file, but not entered into the database yet. When operator A finished typing, the paper-based order are passed to operator B. operator B retypes them all in. As operator B types in an order, it is checked by the software to see if what operator B has typed in is the same as what is held on file. If they are the same, the order is entered into the database. If they are not the same, then an error is flagged up and the order needs t be carefully checked. Flagging up can be done in a number of ways. The keyboard could ‘beep’; an error message could be displayed; or all of the errors saved to file and an error report printed out at the end of the data entry.

Reading back When you purchase something over the phone, you give customer services your details and they type into systems. They can verify that your details are correct simply by reading them back to you and asking you if they are correct. Sometimes, organisations need you to confirm some details they have given you. In this case, they may print out what you told them on a form and then ask you to confirm the details, sign and return it.

Tick the box and click to proceed If you buy something on the Internet, you will typically place on order by typing it in to a form. The order will then be prepared, rearranged and then displayed back on the screen. You will be asked to check it carefully, tick a ‘confirm’ button and then click a ‘proceed’ button. This procedure is another example of a verification method.

A database can still become corrupt It should be recognised that even with clever validation and verification techniques in place, the data entered into a database could still be compromised. For example, it is possible that both operators during validation entered in the same, but wrong data. It is possible that both operators entered in the information on the form, but the information on the form was wrong. Even with the best methods of validation and verification in place, data integrity can still be compromised.

Exercise 1.An operator takes applications for credit cards over the phone. How can she verify that she has taken down all of the details correctly? 2.An operator is re-typing in important data from paper- based forms. State three ways that he could be altered to a verification error.