Computer Science Chapter 6 A foreign key is a column or collection of columns in

subject Type Homework Help
subject Pages 9
subject Words 2280
subject Authors Mary Z. Last, Philip J. Pratt

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Chapter 6: Database Design 2: Design Method
True / False
1. The information-level design methodology involves representing the individual user view as a collection of tables,
refining them to eliminate any problems, and then merging them into a cumulative design.
a.
True
b.
False
2. A design that supports all user views is called a constructive design.
a.
True
b.
False
3. The second step in creating a user view is to represent the user view as a collection of tables.
a.
True
b.
False
4. The first step in creating a user view is to normalize the tables.
a.
True
b.
False
5. When provided with a user view or some sort of stated requirement, you must develop a collection of tables
that will support it.
a.
True
b.
False
6. The primary key is a unique identifier.
a.
True
b.
False
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7. The basic relationships among entities are: one-to-many, many-to-many, and one-to-one.
a.
True
b.
False
8. In a one-to-many relationship, the primary key of the “many” table becomes the foreign key of the “one”
table.
a.
True
b.
False
9. Careful planning in the early stages of the normalization process will usually avoid the need to consider fourth normal
form.
a.
True
b.
False
10. You create a many-to-many relationship by creating a new table whose primary key is the combination of
the primary keys of the original tables.
a.
True
b.
False
11. There are two types of primary keys that you can use in your database design.
a.
True
b.
False
12. A foreign key is a column or collection of columns in one table that is required to match the value of the primary key
for some row in another table, or be null.
a.
True
b.
False
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Chapter 6: Database Design 2: Design Method
13. In DBDL, you represent a table by listing all columns and then underlining the primary key.
a.
True
b.
False
14. In an entity-relationship diagram, rectangles represent foreign keys.
a.
True
b.
False
15. When you use an E-R diagram to represent a database, it visually illustrates all the information listed in the
DBDL.
a.
True
b.
False
16. In an E-R diagram, a dashed line represents an identifying relationship and a solid line represents a nonidentifying
relationship.
a.
True
b.
False
17. Nulls are used when a value is either unknown or inapplicable.
a.
True
b.
False
18. When you combine third normal form tables, the result will always be in third normal form.
a.
True
b.
False
19. The use of an “m” and an “n” in an E-R diagram indicates a many-to-many relationship.
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Chapter 6: Database Design 2: Design Method
a.
True
b.
False
20. A weak entity is a column or collection of columns that could have been chosen as a primary key, but was
not.
a.
True
b.
False
21. A set of requirements that is necessary to support the operations of a particular database user is known as a(n) ____.
a.
user view
b.
user table
c.
user attribute
d.
user field
22. The properties of the entities you choose as you design the user view will become the ____ in the appropriate tables.
a.
rows
b.
columns
c.
data
d.
DBMS
23. If each employee works in a single department and each department has only one employee, the relationship between
employees and departments is ____.
a.
one-to-one
b.
one-to-many
c.
many-to-one
d.
many-to-many
24. A(n) ____ is a primary key that consists of a column that uniquely identifies an entity, such as a person’s Social
Security number.
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Chapter 6: Database Design 2: Design Method
a.
surrogate key
b.
weak entity
c.
artificial key
d.
natural key
25. A column that you create for an entity to serve solely as the primary key and that is visible to users is called a(n) ____.
a.
synthetic key
b.
weak entity
c.
artificial key
d.
natural key
26. A(n) ____ is a system-generated primary key that is usually hidden from users.
a.
weak entity
b.
surrogate key
c.
natural key
d.
artificial key
27. When a DBMS creates a(n) ____ key, it is usually an automatic numbering data type, such as the Access AutoNumber
data type.
a.
surrogate
b.
artificial
c.
natural
d.
logical
28. A natural key is also called a(n) ____ key.
a.
surrogate
b.
intelligent
c.
secondary
d.
defining
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29. Which of the following shows sample DBDL documentation for the Employee table?
a.
Employee (EmployeeNum, LastName, FirstName, Street, City, State, PostalCode)
b.
Employee (EmployeeNum, LastName, FirstName, Street, City, State, PostalCode)
c.
Employee (EmployeeNum, LastName, FirstName, Street, City, State, PostalCode, (WageRate, SocSecNum,
DepartmentNum) )
d.
Employee (EmployeeNum, LastName, FirstName, Street, City, State, PostalCode, WageRate,
SocSecNum, DepartmentNum)
AK SocSecNum
SK LastName
FK DepartmentNumDepartment
30. An alternative to the primary key of a table is listed with the ____ abbreviation in DBDL.
a.
SK
b.
FK
c.
PK
d.
AK
31. Combining the following two tables would result in ____.
Employee (EmployeeNum, LastName, FirstName, WageRate, SocSecNum, DepartmentNum)
Employee (EmployeeNum, LastName, FirstName, Street, City, State, PostalCode)
a.
Employee (EmployeeNum, LastName, FirstName, WageRate, SocSecNum, DepartmentNum, (Street, City,
PostalCode) )
b.
Employee (EmployeeNum, LastName, FirstName, WageRate, SocSecNum, DepartmentNum, Street, City,
State, PostalCode)
c.
Employee (EmployeeNum, LastName, FirstName, Street, City State, PostalCode, WageRate, SocSecNum)
d.
Employee (EmployeeNum, LastName, FirstName, WageRate, SocSecNum, DepartmentNum, EmployeeNum,
LastName, FirstName, Street, City, State, PostalCode )
32. Independent entities have ____ in an E-R diagram
a.
dashed borders
b.
dark backgrounds
c.
square corners
d.
rounded corners
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Chapter 6: Database Design 2: Design Method
33. An entity that does not require a relationship to another entity for identification is called a(n) ____.
a.
alternative entity
b.
foreign entity
c.
independent entity
d.
single entity
34. A relationship that is necessary for identification is called a(n) ____.
a.
objectifying relationship
b.
merging relationship
c.
identifying relationship
d.
referential relationship
35. Convert the following table to first normal form:
Branch (BranchNum, BranchName, (BookCode, Title, OnHand) )
a.
Branch (BranchNum, BranchName)
Book (BookCode, Title)
b.
Branch (BranchNum, BranchName)
c.
Book (BookCode, Title)
d.
Branch (BranchNum, BranchName, BookCode, Title, OnHand )
36. When implementing the physical-level design, for secondary keys, you must ensure that it is possible to retrieve data
rapidly on the basis of a value of the ____ key.
a.
primary
b.
secondary
c.
alternate
d.
foreign
37. After the information-level design is completed, ____ is the next step.
a.
The physical-level design
b.
The modality-level design
c.
The DBMS-level design
d.
The table-level design
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38. When designing a database, you might find it helpful to design a(n) ____ to obtain the required information from
users.
a.
E-R diagram
b.
table
c.
report
d.
survey form
39. The type of information collected on the survey form that describes how data is updated is ____.
a.
Attribute information
b.
Processing information
c.
Relationships
d.
Entity information
40. The crucial issue in making the determination between a single many-to-many-to-many relationship and two (or three)
many-to-many relationships is the ____.
a.
independence
b.
data dependence
c.
redundancy
d.
cardinality
41. If a many-to-many-to-many relationship is created when it is not appropriate to do so, the conversion to ____ normal
form will correct the problem.
a.
first
b.
second
c.
third
d.
fourth
42. A subtype is called a(n) ____ in IDEF1X terminology.
a.
dependent
b.
inner type
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Chapter 6: Database Design 2: Design Method
c.
specification
d.
category
43. In IDEF1X, the ____ is the symbol for category.
a.
square
b.
rectangle
c.
diamond
d.
circle
44. Complete categories are represented by ____ line(s) below the category symbol.
a.
one
b.
two
c.
three
d.
four
45. In the standard E-R diagrams, relationships are drawn as ____, with lines connecting the entities involved in
relationships.
a.
rectangles
b.
diamonds
c.
circles
d.
squares
46. An entity that exists to implement a many-to-many relationship is called a(n) ____.
a.
composite entity
b.
complex entity
c.
complicated entity
d.
circular entity
47. On an E-R diagram, the number closest to the rectangle represents ____ cardinality.
a.
maximum
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Chapter 6: Database Design 2: Design Method
b.
minimum
c.
midvalue
d.
smallest
48. On an E-R diagram, the number closest to the relationship represents ____ cardinality.
a.
maximum
b.
minimum
c.
midvalue
d.
largest
49. ____ means that an entity has a minimum cardinality of zero.
a.
The entity has a mandatory role in the relationship.
b.
The entity is not required in the relationship.
c.
The entity should not be in the relationship as an attribute.
d.
The entity must be listed with all zeroes in the data fields.
50. ____ means that an entity has a minimum cardinality of one.
a.
The entity is required in the relationship.
b.
The entity is not required in the relationship.
c.
The entity should not be in the relationship as an attribute.
d.
The entity must be listed with all ones in the data fields.
51. During the ____________________ design, designers must consider the characteristics of the particular
DBMS that the organization will use.
52. For each table, you must identify the primary key and any alternate keys, secondary keys, and
____________________ keys.
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53. Columns that are of interest strictly for the purpose of retrieval are known as ____________________.
54. It is through foreign keys that you can create relationships among tables and enforce certain types of
____________________ constraints in a database.
55. The style of E-R diagram used in the text is ____________________.
56. ____________________ key restrictions determine the relationships between tables.
57. A relationship that is not necessary for identification is called a(n) ____________________ relationship.
58. On an E-R diagram, ____________________ entities have rounded corners.
59. In the ____________________ design method, specific user requirements are synthesized into a design.
60. The ____________________ design method begins with a general database design that models the overall
enterprise and repeatedly refines the model to achieve a design that supports all necessary applications.
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Chapter 6: Database Design 2: Design Method
61. To obtain information about ____________________ you might ask users questions such as: “If you know a
particular employee number, can you establish other information, such as employee name?”
62. A(n) ____________________ is a special value that represents the absence of a value in a field.
63. You can recognize entity subtypes by the fact the primary key is also a(n) ____________________.
64. An entity-relationship (E-R) model is an approach to representing data in a(n) ____________________.
65. A(n) ____________________ is essentially both an entity and a relationship and is represented in an E-R
diagram by a diamond within a rectangle.
66. When the existence of one entity depends on the existence of another related entity, there is a(n)
____________________.
67. An entity that depends on another entity for its own existence is called a(n) ____________________.
68. A weak entity corresponds to the term ____________________.
69. ____________________ refers to the number of items that must be included in a relationship.
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70. One way to indicate a one-to-many relationship is to place a crow's foot at the ____________________ end
of the relationship.
71. List the steps that must be followed for each user view, as suggested by the information-level design
methodology.
1. Represent the user view as a collection of tables.
2. Normalize these tables.
3. Identify all keys in these tables.
4. Merge the results of Steps 1 through 3 into the cumulative design.
72. Describe the different types of primary keys.
73. List the types of information that must be included on a survey form in order for it to be considered valuable
to the design process.
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74. How can you attempt to avoid the problem of creating a table that is not in third normal form?
75. Explain the difference between a minimum cardinality of zero and a minimum cardinality of one.

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