Database Reference
In-Depth Information
Summary
The chapter opened with an explanation of why field specifications are important and the
benefits you derive from defining them. You learned that defining specifications helps you
establish and enforce
field-level integrity,
enhances overall data integrity, and compels you
to acquire a complete understanding of the nature and purpose of the data in the database.
This level of understanding enables you to leverage the data to your best advantage.
Next,wediscussedtheanatomyofafieldspecification. You'renowfamiliar withthethree
categories of elements within the specification and the sheet you use to record them. We
then discussed each category and its elements in detail. As you now know, the
General
Elements
category represents the most basic attributes of the field. During this discussion,
you learned a set of guidelines that will help you compose a good field description. You
also learned that you could define three types of specifications, thus enabling you to estab-
lishandmaintainconsistentfielddefinitions.Weexaminedthe
Physical Elements
category
next,andyoulearnedthatitpertainstothestructureofthefield.The
Logical Elements
cat-
egory was the last topic of discussion in this section. You now know that it mainly pertains
to a field's values and that it includes elements such as Key Type, Null Support, Range of
Values, Edit Rule, Comparisons Allowed, and Operations Allowed.
Wethendiscussedhowtouseeachtypeofspecification,andyoulearnedasetofguidelines
that will help you determine which one to define for a given field. You also examined
samples of the specifications, and you know how they differ.
The chapter ended with a discussion of defining field specifications for each field. Here
youlearnedthatthebestwaytoensurecompleteandaccuratespecificationsistoworkwith
users and management to define them. You should first define as many specifications as
you can and then work with the staff to define specifications for the remaining fields. You
alsolearnedthatyoucouldworkwithstafftorefinethespecificationsyouinitiallydefined.
Review Questions
