Establishing Table Structures - Database Design for Mere Mortals - page 193

We then discussed the process of associating fields with each table on the Final Table List.
Here you learned how to build a structure for a given table using fields from the Prelimin-
ary Field List that best represent characteristics of the table's subject.
Refining fields was the next subject of discussion, and you learned a set of guidelines for
creatingfieldnamesthatwillhelpyouensurethattheyareclear,descriptive, andmeaning-
ful. You also learned about the Elements of the Ideal Field. Now you know that you can
resolve anomalies in a field by determining whether it complies with these elements. We
then discussed how to resolve multipart and multivalued fields. You learned that decom-
posing multipart fields yields new fields, whereas decomposing multivalued fields yields
new tables.
Thechapterclosedwithadiscussionofrefiningtablestructures.Youlearnedtoidentifythe
Elements of the Ideal Table, and you now know that you can ferret out a problem in table
structure by determining whether a table complies with these elements. We then discussed
unnecessary duplicate fields, and you now know that they appear in a table for one of two
reasons: to supply reference information or to represent different occurrences of the same
type of value. You then learned how to resolve duplicate fields to eliminate the problems
they present.
The final discussion centered on the topic of subset tables. As you now know, a subset
table represents a subordinate subject of a particular data table, and there is a distinct rela-
tionship between the subset table and the data table. You also know that you can explicitly
createsubsettables.Youthenlearnedthatyoumayhaveunknowinglycreatedsubsettables
earlier in the database design process and that you need to look for subset tables you have
not previously identified. When you identify a subset table, you refine it and add it to the
Final Table List.
Review Questions
1 . How do you identify and establish tables for a new database?
2 . Why do you use the Preliminary Field List to help you define tables for the data-
base?
3 . Whatactiondoyoutakewhenanitemonthelistofsubjectsandadifferentlynamed
item on the Preliminary Table List both represent the same subject?
4 . What information does the Final Table List provide?
5 . State three guidelines for creating table names.
6 . State two guidelines for composing table descriptions.
7 . How do you assign fields to a table on the Final Table List?