Database Reference
In-Depth Information
A Side Note: Value Lists
As you examine the characteristics on a database, spreadsheet, or web page sample, record
onasheetofpaperthenameofeachcharacteristicthatincorporatesa
value list
(alsoknown
as an
enumerated list
). This list specifies the acceptable range of values for a particular
characteristic and often enforces a given business rule. (You'll learn about business rules
in
Chapter 11
,
“
Business Rules
.”) For example, say you work for a manufacturing com-
panythatusesfourspecificvendorstodeliveritsgoodstocustomersacrossthenation.You
coulduseavaluelisttoensurethatauserselectsoneofthosefourvendorstoshipapartic-
ularorder.
Figure6.16
illustratesthisexample(noteShipVia)andalsoshowstwocommon
types of value list.
Figure 6.16. A database screen with two value lists
When you record the name of a characteristic that incorporates a value list, also record the
values within the list. If the list contains a large number of values, write a brief description
of the type of values in the list and (if possible) a minimum and maximum value; other-
wise, write down each of the values.
Figure 6.17
shows an example of the record you're
creating.
