Database Reference
In-Depth Information
Note
The guideline for using a plural form for a table name is a particularly good one
while you're working on the logical design of the database. It makes it very easy
to differentiate table names from field names, especially when you're displaying
them on a projection screen or when you've written them all across a white board
in a conference room.
Keep in mind, however, that the table names are likely to change once you (or the
database developer in charge of implementing the database) begin implementing
the database into a specific RDBMS application. The names will then need to con-
form to the naming convention that developers commonly use for the RDBMS.
Indicating the Table Types
Asyoulearnedearlierinthischapter,youindicateeachtable'stypeontheFinalTableList.
Recall that the four classifications you can use to identify the table type are
data, linking,
subset,
and
validation.
When you first create your Final Table List, every item on the list is a
data
table because it
represents a subject that is important to the organization and serves as the primary found-
ation of the information that the database provides. There will be no
linking
tables or
val-
idation
tables on the list because you have not yet defined relationships or imposed data
integrity. (You'll address these issues later in the design process.) The list will not contain
subset
tables because you define them
after
you assign fields to the data tables.
For the moment, designate each table on the Final Table List as a data table. You'll assign
other table types later as the database design process continues to unfold.
Composing the Table Descriptions
The
table description
is another aspect of a table that you record on the Final Table List.
A table description is crucial because it helps everyone understand why a given table ex-
ists and why the organization is concerned with collecting the data for that table. In fact,
the description must
explicitly define the table
and
state its importance
to the organization.
It doesn't matter whether the definition comes first or you use more than one sentence to
convey this information—both the definition and the explanation of the table's importance
must be in the description. The table description also provides a means of validating the
need for a table—if you are unable to explain why a table is important to the organization,
then you need to determine when and how the table was identified and whether it really is
necessary at all.
