Database Reference
In-Depth Information
Reviewing Data Integrity
The seventh and final phase in the database design process involves reviewing the final
database structure for data integrity.
First, you review each table to ensure that it meets the criteria of a properly designed table
andyoucheckthefieldswithineachtableforproperstructure.Youthenresolveanyincon-
sistencies or problems you encounter and review the structures once more. After you've
made the appropriate refinements, you check table-level integrity.
Second, you review and check the field specifications for each field. You make necessary
refinements to the fields and then check field-level integrity. This review reaffirms the
field-level integrity you identified and established earlier in the database design process.
Third, you review the validity of each relationship, confirm the relationship type, and con-
firmtheparticipationcharacteristics foreachtablewithintherelationship.Youthenreview
relationship integrity to ensure that there are matching values between shared fields and
that there are noproblems inserting, updating, ordeleting data ineither ofthe tables within
the relationship.
Finally,youreview the business rules that youidentified earlier inthe database design pro-
cess and confirm the constraints you've placed on various aspects of the database. If there
are any other limitations that have come to your attention since the last set of personnel
interviews, you establish them as new business rules and add them to the existing set of
business rules.
You're ready to implement your logical database structure in an RDBMS program once
you've completed the entire database design process. However, the process is never
really
complete because the database structure will always need refinement as your organization
evolves.
Summary
We began this chapter with a discussion of the importance of completing the design pro-
cess,andyoulearnedthatdesigningadatabasewithoutthebenefitofagooddesignmethod
leads to poor and improper design. We also discussed the fact that the level of structural
and data integrity is in direct proportion to how thoroughly you follow the design process.
You then learned that inconsistent data and inaccurate information are two problems typic-
ally associated with poorly designed databases.
Nextwelookedatanoverviewoftheentiredatabasedesignprocess.Theprocesswascon-
solidated into the following phases in order to provide you with a clear picture of the gen-
eral steps involved in designing a database.