Midterm 2017, questions and answers PDF

Preview

Summary

Midterm 2017, questions and answers...

Description

ITC114/423 Mid Term Revision Student Name: ________________________________ ID: __________________

Please circle the correct answer

1. 1NF, 2NF, and 3NF are ____. a. normalization stages p. 148 b. anomalies c. repeating groups d. atomic attributes 1. A table where every determinant is a candidate key is said to be in ____. a. b. c. d.

BCNF 2NF 3NF 4NF

p.164

2. Which of the following should not be placed in a relational table? a. Entity b. Attribute c. Relationship d. Repeating group p.152

3. An attribute that is part of a key is known as a(n) ____ attribute. a. important b. nonprime c. prime p.152 d. entity 4. An attribute that cannot be further divided is said to display: Atomicity refer p.152

2. The ERD is used to graphically represent the _____________ database model. a. b. c. d.

condensed physical logical conceptual

p.103

3. ____________________ expresses the specific number of entity occurrences associated with one occurrence of the related entity. Cardinality -- p.104

4. The Chen model is especially useful to illustrate the database from a(n) ____ perspective. a. b. c. d.

developmental conceptual p.103 actual specific

5. A derived attribute ____. a. b. c. d.

must be stored physically within the database need not be physically stored within the database p.108 has many values must be based on the value of three or more attributes

6. A ____ attribute can be further subdivided to yield additional attributes. a. b. c. d.

composite simple single-valued multivalued

p.105

5. If an entity’s existence depends on the existence of one or more other entities, it is said to be ____-dependent. a. b. c. d.

existence relationship business weak

p.110

7. The bridge entity is known as a ____ entity. a. b. c. d.

unary weak strong composite

p. 122

8. The referential integrity rule requires that ____. a. every null foreign key value must reference an existing primary key value b. an attribute have a corresponding value c. every non-null foreign key value reference an existing primary key value d. you delete a row in one table whose primary key does not have a matching foreign key value in another table

6. In a relationship, when a primary key from one table is also defined in a second table, the field is referred to as a ____ in the second table. a. b. c. d.

combined key redundant field primary key foreign key

p. 86

9. A ____ is any key that identifies each entity uniquely. It functionally determines all of the entity's attributes. a. b. c. d.

superkey primary key foreign key combined key

p.86

10. A relational operator that combines all rows from two tables is considered to be a(n) ____. a. b. c. d.

UNION INTERSECT DIFFERENCE PRODUCT

p. 71

11. A relational operator that yields values from all rows in a table is known as the ____ operator. a. b. c. d.

DIFFERENCE PRODUCT SELECT PROJECT

p. 72

12. A relational operator that allows for the combination of information from two or more tables is known as the ____ operator. a. b. c. d.

SELECT PROJECT JOIN p. 74 DIFFERENCE

13. Each table column represents a(n) ____________________ and has a distinct name. Attribute p. 62 14. The _Logical p. 61___ view of a relational database is facilitated by the creation of data relationships based on a construct known as a table. 15. A relational database model ____. a. b. c. d.

does not require substantial hardware and system software overhead does not promote "islands of information" problems allows trained people to use a good system poorly lets the user operate in a human logical environment p. 36

16. Database models can be grouped into two categories: conceptual models and ____ models. a. b. c. d.

implementation logical physical query

p. 43-46

17. Which of the following is least likely to be a business rule as relates to data modelling? a. A customer may make many payments on an account. b. A machine operator may not work more than 10 hours in a 24-hour period. c. A training session cannot be scheduled for fewer than 10 employees or more than employees. d. Casual Fridays take place in the summer. P. 31

18. In the relational model, another name for a table is a(n) ____________________. Relation p. 33 19. The ____ depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities). a.

subtype discriminator

b. c. d.

inheritance specialization hierarchy entity supertype

p.185

20. The relationships depicted within the ____ are sometimes described in terms of "IS-A" relationships. a. b. c. d.

subtype discriminator inheritance specialization hierarchy entity supertype

p.185

21. ____ is the bottom-up process of identifying a higher-level, more generic entity supertype from lower-level entity subtypes. a. b. c. d.

Specialization Generalization Partial completeness Total completeness

p. 195

22. Surrogate primary keys are especially helpful when there is no ____. a. b. c. d.

primary key natural key foreign key Surrogate key

p. 195

23. What do specialization hierarchies do? What do they provide the means to?

24. Describe the importance of the Data Modeling Checklist, including all details....