Database Reference
In-Depth Information
Figure 9.10. Customized Replica field specifications for the V
END
S
TATE
field
Here are a few things to note about this specification.
1.
The field name (V
END
S
TATE
) accurately denotes what the field represents.
2.
The label (“State”) is what the user will see on visual displays and printed docu-
ments.
3.
The Source Specification general element properly references the generic S
TATE
field's specification.
4.
The Description element is now specific to this field. Recall that the description is
more general in the source specification.
5.
A default value has been set for this field; there is no such value in the source spe-
cification.
6.
The Range of Values element is now specific to this field; it was much broader in
the source specification.
In the next chapter, you'll learn how to define a Replica field specification for a field that
serves as a foreign key.
Defining Field Specifications for Each Field in the Database
Now that you have all the necessary fields assigned to each table and you understand the
various elements within a field specification, you can begin the process of defining a field
specificationforeachfieldinthedatabase.Itwilltakeyouaconsiderableamountoftimeto
complete this process, but remember that you're working diligently to establish field-level
integrity by ensuring that the data is consistent, valid, and as free from errors as possible.
All your hard work will pay great dividends because the information you retrieve from the
database will always be timely and accurate, and you will have a reliable set of structural
blueprints you can use when you implement the database in an RDBMS program.
You can ensure that the specifications are as complete and accurate as possible by working
with both users and management to define them. They can provide insights into the data
and can be of special assistance in refining the specification's logical elements. You don't
have to speak with
everyone
in the organization, but you do want to assemble and meet
with a representative number of people who are very familiar with the data and how it is
used. Schedule as many meetings as are necessary (or possible) to complete the interview
process, and take the time you need to be as thorough as you can. Above all,
do not
rush
through this phase! Doing so just diminishes the benefits of your overall efforts and in-
creases your chances of making unnecessary mistakes.
