Database Reference
In-Depth Information
Figure 11.23. A completed Business Rule Specifications sheet
Nowyourepeatthisprocessfortheremainingrelationships.Whenyou'refinished,thepro-
cess is complete and you're ready for the next stage of the database design process.
Summary
This chapter opened with a definition of
business rules.
You learned that a business rule is
a constraint imposed on a field or a relationship that is based on the way the organization
perceives and uses its data and that it is derived from the manner in which the organiza-
tion functions or conducts its business. You now know that there are two major types of
business rules:
database oriented
and
application oriented.
Although our focus here is on
database-oriented business rules, you know that you can at least record the basic elements
of application-oriented business rules for use later in the implementation process.
You then learned that database-oriented business rules are divided into two categories:
field-specific
business rules, which affect the elements of a field specification for a par-
ticular field; and
relationship-specific
business rules, which affect the characteristics of a
relationship.
The chapter continued with a discussion of defining and establishing business rules. Here
youlearnedthatyouworkwithusersandmanagementtodefinethebusinessrulesrequired
by the organization. You also learned that it is best to establish the field-specific business
rules first, followed by the relationship-specific business rules.
Next, you learned the steps necessary to define and establish each type of business rule.
You now know that, in general, you work with a field or relationship, review the field or
relationship in light of the rule to determine whether any constraints are necessary, define
theappropriatebusinessrule,establishtherulebymodifyingtheappropriatefieldspecific-
ation elements or relationship characteristics, decide which actions test the rule, and then
complete a Business Rule Specifications sheet for the rule.
The chapter continued with a discussion of the elements of the Business Rule Specifica-
tions sheet, and how each element on the sheet is defined. As you now know, using Busi-
ness Rule Specifications sheets allows you to document all of your rules and provides you
with a standard method for recording and reviewing them.
We closed the chapter by discussing
validation tables.
You learned that you can create and
use a validation table to support a business rule that limits the range of values for a par-
ticular field. In this manner, the validation table helps to enforce data integrity. You also
learnedthatyouneedtoestablishnewrelationshipswhenyouusevalidationtablesandthat
theserelationshipshavethesametypesofcharacteristicsasanyothertypesofrelationships
in the database.
