Database Reference
In-Depth Information
instead of directly on that entity's primary key. We therefore complete the following tem-
plate for those entities that have more than two attribute:
Question
Yes? No?
Is
Organization Name
a fact about any other attribute in
Organization
?
✓
Is
Organization First Survey Date
a fact about any other attribute in
Organization
?
✓
Is
Survey Question Label Name
a fact about any other attribute in
Survey Question
?
✓
Is
Survey Question Description
a fact about any other attribute in
Survey Question
?
✓
Is
Survey Question Singular Response Indicator
a fact about any other attribute in
Survey Question
?
✓
Is
Survey Respondent First Name
a fact about any other attribute in
Possible Answer
?
✓
Is
Survey Respondent Last Name
a fact about any other attribute in
Possible Answer
?
✓
Because there are no hidden dependencies on our data model, there are no changes to make,
and the model remains unchanged from our 2NF model.
Abstraction (Relational Only)
Recall that abstraction brings flexibility to a design by redefining and combining some of
the attributes, entities, and relationships within the model into more generic terms.
The general question that needs to be asked is:
“Are there any entities, relationships, or data elements that should be made more generic to
accommodate future requirements?”
For our survey data model, I do not believe there are any valuable opportunities to abstract.
We applied some abstraction in viewing everything on the survey form as a question. We
can abstract
Survey Respondent
and
Organization
into the generic
Party
concept, as a
Party
can be either a person or organization, and each
Party
can play many roles such
