Database Reference
In-Depth Information
keep these objectives in mind and constantly focus on them while you're designing your
database.
•
The database supports both required and ad hoc information retrieval.
The data-
base must store the data necessary to support information requirements defined
during the design process and any possible ad hoc queries that may be posed by a
user.
•
The tables are constructed properly and efficiently.
Each table in the database rep-
resents a single subject, is composed of relatively distinct fields, keeps redundant
data to an absolute minimum, and is identified throughout the database by a field
with unique values.
•
Data integrity is imposed at the field, table, and relationship levels.
These levels of
integrity help guarantee that the data structures and their values will be valid and
accurate at all times.
•
The database supports business rules relevant to the organization.
The data must
provide valid and accurate information that is always meaningful to the business.
•
The database lends itself to future growth.
The database structure should be easy to
modify or expand as the information requirements of the business change and
grow.
Youmightfinditdifficultattimestofulfilltheseobjectives,butyou'llcertainlybepleased
with your final database structure once you've met them.
Benefits of Good Design
Thetimeyouinvestindesigningasounddatabasestructureistimewellspent.Gooddesign
saves
you time in the long run because you do not constantly have to revamp a quickly and
poorly designed structure. You gain the following benefits when you apply good design
techniques.
•
The database structure is easy to modify and maintain.
Modifications you make to
a field or table will not adversely affect other fields or tables in the database.
•
The data is easy to modify.
Changes you make to the value of a given field in a
table will not adversely affect the values of other fields within the table. Further-
more, a well-designed database keeps duplicate fields to an absolute minimum, so
you typically modify a particular data value in one field only.
•
Information is easy to retrieve.
You'll be able to create queries easily because the
tables are well constructed and the relationships between them are properly estab-
lished.
