An employee keeps track of her customers using a CUSTOMER file containing the fo
ID: 3510485 • Letter: A
Question
An employee keeps track of her customers using a CUSTOMER file containing the following data:
The file is updated by the employee to:
Change Mrs. Jane Hoffman's phone number to "865-433-4235".
Add customer named “Mr. Yaron Hether” with a phone number of “555-999-1212”, the item purchased as “Compass”, and the amount charged as “19.99”
After modification, the file contains the following:
Select all answers that are errors that the employee made during modification.
a.Structural independence
b. Created data inconsistencies because of the different phone numbers for Jane Hoffman
c. Update anomaly
d. Deletion anomaly
a.Structural independence
b. Created data inconsistencies because of the different phone numbers for Jane Hoffman
c. Update anomaly
d. Deletion anomaly
NAME PHONE ITEM_PURCHASED Mrs. Jane Hoffman 865-426-9987 Bag Flashlight AMOUNT_CHARGED $99.99 $43.95 Mr. Eli Jordan 552-342-3421 John Smith Esquire 153-332-1038 Compass $19.99 Hon. Patrick Lode 281-475-8329 Watch $300.00 Backpack 821-293-8875 865-426-9987 153-332-1038 $159.99 $45.23 Ms. Angel Glass Mrs. Jane Hoffman John Smith Esquire Mrs, Jane Hoffman Mr. Jordan Rock Watch Magnifying Glass $20.00 $19.99 865-426-9987 Compass 103-382-9931 Gloves $35.00Explanation / Answer
Answer is B and D
B and D are errors
A and b are correct
Structural independence exists when it is possible to make changes in the file structure without affecting the application programs ability to access the data. It is important because without it any changes such as adding a field would render applications which access the new file structure inoperable.
An update anomaly is a data inconsistency that results from data redundancy and a partial update. For example, each employee in a company has a department associated with them as well as the student group they participate in.
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