2004Spring :CS 157 First midterm study guide

"I see and I forget, I hear and I remember, I do and I understand." -----------Confucius

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• Name and briefly describe the function of each major component of a database.
• ANSI/SPARC Architecture 3 levels.
• Explain the features and functions of one of the DBMS ‘s subsystems (design tools, run-time, or engine)
• Basic motivation and database terminology

• Entity-relationship model and E/R diagrams

• Entity sets, relationship sets, attributes, keys, roles
• Multiplicity of relationship sets (one-to-one, one-to-many, etc.)
• Weak entity sets

• Relate, or distinguish between, the following terms: foreign key and primary key. Give an example that relates these terms.
• Relate, or distinguish among, the following terms: entity, attribute, identifier, and relationship
• List and give examples of the three types of relationships.
• Distinguish between the maximum and minimum cardinality of entity relationships
• Relate, or distinguish between, the terms: weak entity, strong entity.
• Subclasses ("isa" relationships)

 

 

 

 

 

 

 

 

 

PREPARE FOR WRITING EXAMINATION

1. STUDY-- Read the material which the exam will cover.

A. Formulate possible study questions, our use any study questions made available to you.

B. Arrange your material (Notes, (Note cards) so that you can anticipate an answer to one or more of the study questions.

2. Know the exam conditions and be prepared to meet those conditions. (Since you most likely will have limited time, select and arrange those materials which will best help you present what you know about the subject and help you show that you can control that material.

3. Before writing the exam, read all the questions. Choose that question which comes closest to those you formulated on your own and which most closely relates to those materials you have studied, reviewed, and arranged.

4. While writing the exam--

A. Be sure to CLEARLY and CONCISELY and PRECISELY answer the question.

B. Make sure the discussion subsequent to your answer follows clearly from your answer:

Your topic sentences should relate back to your answer. Your topic sentences should be supported by CLEAR, SPECIFIC references to your materials (i.e., your sources).

C. Make sure you have a conclusion with summarizes the key points of your answer and offers some insight as to what you learned from writing on the question.

D. Try to finish in time to edit (proofread) your answer for the most obvious problems. Or, try to edit those problems as you go.

Sample Problems.

1. Construct an E-R diagram for a car insurance company with a set of customers (name, ss#) each of which owns a number of cars (maker, model, year). With each car a record of accidents (date, driver, damage-amount) in which the car was involved is also maintained.
2. Construct an E-R diagram for a hospital with a set of patients (name, ss#) and a set of medical doctors (name, specialty). With each patient, a log of various conducted tests is also associated.
3. What is data abstraction? What is the relationship between data abstraction and conceptual data models?
4. What is the difference between the conceptual level and the view level?
5. What is a data definition language used for? At what level of (data) abstraction is it used?.
6. Consider the following E-R diagram for a genealogy database:



1. Find all candidate keys for each entity set and designate a primary key for each. Document any assumptions about entities that affect the choice of candidate keys.
2. Compute a superkey for each relationship set using the algorithm given in class. Find all candidate keys that are subsets of this superkey. Document any assumptions that affect the choice of candidate keys.
3. Give the relation schemes of the relations that these entity and relationship sets would be reduced to.
4. What does the arrowhead on the link between child and marriage mean? What does the presence of the arrowhead say about the relationship between children and marriages?