Database Reference
In-Depth Information
•
There are two techniques for creating a generic or semantic data model: (1)
the object-based modeling technique and (2) the entity-relationship modeling
technique.
•
Data views form the underlying basis for creating a data model; data views can
be perceived as a collection of information requirements and as windows into
the database system.
•
There are two methods for data view integration: (1) merging individual user
views and (2) integrating partial data models.
REVIEW QUESTIONS
1. Give a simple definition of a data model. Explain the connection between
real-world information and the data model.
2. State any four reasons for creating a data model during DDLC. Is creating
a data model absolutely essential?
3. What do you understand by “real-world information”? What would real-
world information be for a banking organization?
4. Data model components need notations or symbols to represent them. List
any such five data model components.
5. What is filtering out of irrelevant data? How is this important in data mod-
eling?
6. What is your understanding of a generic, semantic data model? How does it
differ from a conventional data model as specified in the text?
7. Name the two common modeling techniques for creating a semantic data
model. What are the differences between the two techniques?
8. How do CASE tools aid data modeling?
9. Explain briefly the role of data views in data modeling.
10. What is view integration? Briefly describe any one method for view
integration.
EXERCISES
1. Match the columns:
1. real-world information
A. technique for creating semantic data
model
2. semantic data model
B. reconcile naming conflicts
3. special object type
C. window into data system
4. E-R modeling
D. expresses true meaning of data
5. CASE tools
E. integrated from partial data models
6. data view
F. based on data models
7. merging user views
G. represented by data model
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