Database Reference
In-Depth Information
2
Orders requiring more
than one spreadsheet row
Customer
Order
Part
Part
Number
Quoted
Rep
Number
Customer Name
Number
Order Date
Number
Description
Ordered
Price
Warehouse
Number
148
Al's Appliance
21608
10/20/2013
AT94
Iron
11
$21.95
3
20
and Sport
148
Al's Appliance
21619
10/23/2013
DR93
Gas Range
1
$495.00
2
20
and Sport
282
Brookings
21614
10/21/2013
KT03
Dishwasher
2
$595.00
3
35
Direct
356
Ferguson's
21610
10/20/2013
DR93
Gas Range
1
$495.00
2
65
356
Ferguson's
21610
10/20/2013
DW11
Washer
1
$399.99
3
65
408
The Everything
21613
10/21/2013
KL62
Dryer
4
$329.95
1
35
Shop
608
Johnson's
21617
10/23/2013
BV06
Home Gym
2
$794.95
2
65
Department
Store
608
Johnson's
21617
10/23/2013
CD52
Microwave
4
$150.00
1
65
Department
Oven
Store
608
Johnson's
21623
10/23/2013
KV29
Treadmill
2
$1,290.00
2
65
Department
Store
FIGURE 1-1
Sample orders spreadsheet
Redundancy is one problem that employees have with the orders spreadsheet. Redundancy is the dupli-
cation of data or the storing of the same data in more than one place. In the orders spreadsheet, redundancy
occurs in the Customer Name column because the name of a customer is stored in more than one place. All
three rows for customer number 608, for example, store
as the customer
name. In the orders spreadsheet, redundancy also occurs in other columns, such as the Order Date and
Part Description columns.
Johnson
'
s Department Store
Q&A
Question: What problems does redundancy cause?
Answer: Redundancy wastes space because you're storing the same data in multiple places. The extra space
results in larger spreadsheets that require more space in memory and on disk and that take longer to save
and open.
When you need to change data, redundancy also makes your changes more cumbersome and time-
consuming. For example, if you incorrectly enter “Johnson's Department Store” in the Customer Name col-
umn, you would need to correct it in three places. Even if you use the global find-and-replace feature,
multiple changes require more computer time than does a single change.
Finally, redundancy can lead to inconsistencies. For example, you might enter “Johnson's Department
Store,”“Johnsons Department Store,” and “Johnsons' Department Store” in the Customer Name column, and
then not be sure which is the correct spelling. Further, if that customer's name is spelled three different ways
and you use the search feature with one of the three values, you'd find a single match instead of three
matches.
Difficulty accessing related data is another problem that employees at Premiere Products encounter with
their spreadsheets. For example, if you want to see a customer
'
s address and a part
'
s standard price, you
must open and search other spreadsheets that contain this data.
Spreadsheets also have limited security features to protect data from being accessed by unauthorized
users. A spreadsheet
'
s data-sharing features also prevent multiple employees from updating data in one
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