INF3703/201/1/2011
PRINCIPLES OF DATABASES
Tutorial Letter 201/
Studiebrief 201
CONTENTS / INHOUD:
Solution to assignment 1 / Oplossing vir werkopdrag 1
SCHOOL OF COMPUTING
SKOOL VIR REKENAARKUNDE
INF3703/2011
1. Solutions to Assignment 1
Identify the choice that best completes the statement or answers the question.
1.
The relational database model enables you to view data ____ rather than ____.
(P70)
1. relationally, hierarchically
2 hierarchically, relationally
3. physically, logically
4 logically, physically
2.
The relational model’s creator, E. F. Codd, used the term relation as a synonym
for ____. (P41)
1. index
2. key
3. Table
4. Relationship
3.
A(n) ____ is perceived as a two-dimensional structure composed of rows and
columns. (P79)
1. Table
2. Rowset
3. Attribute
4. intersection
4.
Date attributes contain calendar dates stored in a special format known as the
____ date format. (P62)
1. Epoch
2. Calendar
3. Julian
4. logical
5.
____ data can have only a true or false (yes or no) condition.
1. Logical
2. Character
3. Date
4. Numeric
6.
The attribute B is ____ the attribute A if each value in column A determines
one and only one value in column B. (P77)
1. logically dependent on
2. owned by
3. determined by
4. functionally dependent on
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7.
Any attribute that is part of a key is known as a ____. (P77)
1. key attribute
2. logical attribute
3. key determiner
4. selector
8.
If the attribute (B) is functionally dependent on a composite key (A) but not on
any subset of that ____ key, the attribute (B) is fully functionally dependent
on (A). (p77-78)
1. foreign
2. unique
3. composite
4. complete
9.
In the following table description, ____ is the primary key.
PRODUCT (PROD_CODE, PROD_DESCRIPT, PROD_PRICE,
PROD_ON_HAND, VEND_CODE) . (P79)
1. PROD_DESCRIPT
2. PROD_CODE
3. PROD_PRICE
4. PROD_ON_HAND
10.
Referential ____ means that if the foreign key contains a value, that value refers
to an existing valid tuple (row) in another relation. (P81)
1. integrity
2. uniqueness
3. direction
4. relations
11.
Attributes may share a ____. (P158)
1. name
2. domain
3. location
4. table
12.
In an ER diagram, primary keys are indicated by ____. (P79)
1. bolding
2. italics
3. underlining
4. a special font
13.
A ____ should be a derived attribute. (P79)
1. Person’s name
2. Person’s age
3. Person’s social security number
4. Person’s phone number
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14.
A derived attribute ____. (P162)
1. must be stored physically within the database
2. Need not be physically stored within the database
3. has many values
4. must be based on the value of three or more attributes
15.
A relationship is an association between ____. (P163)
1. objects
2. entities
3. databases
4. fields
16.
In the ERD, cardinality is indicated using the ____ notation.
1. (max, min)
2. (min, max)
3. [min ... max]
4. {min|max}
17.
If an entity’s existence depends on the existence of one or more other entities, it
is said to be ____-dependent.
(P166)
1. existence
2. relationship
3. business
4. weak
18.
A ____ relationship exists when three entities are associated. (P175)
1. unary
2. binary
3. ternary
4. weak
19.
____ is a generic entity type that is related to one or more entity subtypes.
(P213)
1. A subtype discriminator
2. Inheritance
3. A specialization hierarchy
4. An entity supertype
20.
The relationships depicted within the ____ are sometimes described in terms of
"is-a" relationships. (P213)
1. subtype discriminator
2. inheritance
3. specialization hierarchy
4. entity supertype
(P164-165)
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21.
A specialization hierarchy can have ____ level(s) of supertype/subtype
relationships. (P213)
1. zero
2. only one
3. one or many
4. many
22.
In the specialization hierarchy there is a ____ relationship between a subtype
and supertype. (P213)
1. self-referring
2. 1:1
3. 1:M
4. M:N
23.
Overlapping subtypes are subtypes that contain ____ subsets of the supertype
entity set. (P216)
1. entity
2. subtypes
3. unique
4. nonunique
24.
The “____” characteristic of a primary key states that:
The PK must uniquely identify each entity instance. A primary key must be
able to guarantee unique values. It cannot contain nulls. (P223)
1. unique values
2. nonintelligent
3. preferably single-attribute
4. security complaint
25.
The “____” characteristic of a primary key states that:
The selected primary key must not be composed of any attribute(s) that might
be considered a security risk or violation. For example, using a Social Security
number as a PK in an EMPLOYEE table is not a good idea. (P224)
1. unique values
2. nonintelligent
3. preferably single-attribute
4. security complaint
26..
Composite primary keys are particularly useful as identifiers of composite
entities, where each primary key combination is allowed only once in the ____
relationship. (P224)
1. 0:1
2. 1:1
3. 1:M
4. M:N
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27.
Surrogate primary keys are especially helpful when there is no ___key. (P227)
1. primary
2. natural
3. foreign
4. composite
28.
Data redundancy produces ____. (P246)
1. slower lookups
2. robust design
3. efficient storage use
4. data integrity problems
29.
Converting a ____ is not an example of denormalization. (P246)
1. 3NF to 2NF
2. 2NF to 1NF
3. 3NF to 1NF
4. 3NF to BCNF
30.
A(n) ____ should not be placed in a relational table. (P251)
1. entity
2. attribute
3. relationship
4. repeating group
31.
In a(n) ____ diagram, the arrows above the attributes indicate all desirable
dependencies. (P253)
1. Chen
2. dependency
3. functionality
4. ER
32.
A table that is in 1NF and includes no partial dependencies only is said to be in
____. (P256-257)
1. BCNF
2. 2NF
3. 3NF
4. 4NF
33.
Granularity refers to ____. (P259)
1. the size of a table
2. the level of detail represented by the values stored in a table's row
3. the number of attributes in a table
4. the number of rows in a table
34.
To generate a surrogate key, Microsoft Access uses a(n) ____ data type. (P263)
1. surrogate
2. sequence
3. AutoNumber
4. identity
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35.
Most designers consider the BCNF as a special case of the ____. (P 264)
1. 1NF
2. 2NF
3. 3NF
4. 4NF
--The end—
Unisa 2011
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