Database Reference
In-Depth Information
lysis stage of the design process. You can keep each of these items in a separate appendix
at the end of the documentation.
Alloftheseitemsconstitutethecompletesetofdocumentationforthelogicaldesignofthe
database. This documentation is vital for three reasons.
1.
It provides a complete record of the database structure.
You can find every aspect
of the logical structure of the database within the documentation. Additionally, you
can answer almost any question concerning the database simply by referring to the
documentation.
2.
It provides a complete set of specifications and instructions on how the database
should be created during the implementation process.
This documentation is simil-
ar to an architect's blueprints: It indicates how the database is to be constructed. It
also identifies the integrity that needs to be established for the database. Because
the database design is not directed to a particular RDBMS, the individuals imple-
menting the database have full latitude concerning the manner in which they phys-
ically implement the database.
3.
Should it seem necessary to modify the database structure during the implementa-
tion process, the design documentation can be used to determine the effects and
consequences of any modifications.
Any modifications you make to the database
structure should be the result of an informed decision. You can make certain that a
proposed modification will not have an adverse effect on the database structure by
referencing the documentation first.
Done at Last!
Now that you've completed the integrity review and assembled all of the documentation
for the database, the logical database design process is complete. You can rest assured that
you have a properly designed database and that its implementation will proceed smoothly.
On to the next client and the next database design!
Case Study—Wrap-Up
This is your last meeting with Mike and his staff. Your objective is to review his database
and its integrity one final time. Although you're confident that you will not find any prob-
lems, you want to give the database one final quality-control review.
During the meeting, you review each of the database structures to ensure that they are in
accordance with the various elements that govern them. Then you review each component
of overall data integrity to make certain that you've properly established table-level, field-
level,andrelationship-levelintegrity,aswellasbusinessrules.Finally,yougatherallofthe
documentation you've generated throughout the design process. After you've assembled
