final dbm Flashcards
1
Q
The entity relationship diagram (ERD) represents the \_\_\_\_\_ database as viewed by the end user. A. condensed B. physical C. logical D. conceptual
A
D. conceptual
2
Q
A derived attribute is indicated in the Chen notation by a \_\_\_\_\_ that connects the attribute and an entity. A. single line B. dashed line C. double dashed line D. double line
A
B. Dashed line
3
Q
Ideally, an entity identifier is composed of \_\_\_\_\_ attribute(s). A. one B. two C. three D. six
A
A. One
4
Q
If an entity can exist apart from all of its related entities, then it is existence-independent, and it is referred to as a(n) \_\_\_\_\_ entity. A. weak B. alone C. unary D. strong
A
D. Strong
5
Q
An entity in the entity relationship model corresponds to a table in the relational environment.
A. True
B. False
A
A. True
6
Q
The \_\_\_\_\_ notation of entity-relationship modelling can be used for both conceptual and implementation modelling. A. Bachman B. UML C. Chen D. Crow's Foot
A
B. UML
7
Q
The conceptual model can handle \_\_\_\_\_ relationships and multivalued attributes. A. 1:1 B. M:N C. 1:M D. 1:N
A
B. M:N
8
Q
The Crow’s Foot notation is less implementation-oriented than the Chen notation.
A. True
B. False
A
B. False
9
Q
If Tiny College has some departments that are classified as “research only” and do not offer courses, the COURSE entity of the college database would be \_\_\_\_\_ the DEPARTMENT entity. A. existence-dependent on B. independent of C. mandatory for D. optional to
A
D. Optional to
10
Q
A relationship is an association between \_\_\_\_\_. A. objects B. entities C. databases D. fields
A
B. Entities
11
Q
In Chen notation, there is no way to represent cardinality.
A. True
B. False
A
B. False
12
Q
Software vendors have adopted the Chen representation because of its compact representation.
A. True
B. False
A
B. False
13
Q
A(n) \_\_\_\_\_ is the set of possible values for a given attribute. A. domain B. range C. identifier D. key
A
A. Domain
14
Q
The first step in building an entity-relationship diagram (ERD) is _____.
A. developing the initial ERD
B. creating a detailed narrative of the organization’s description of operations
C. identifying the attributes and primary keys that adequately describe the entities
D. identifying the business rules based on the description of operations
A
B. Creating a detailed narrative of the organization’s description of operations
15
Q
Referential integrity and participation are both bidirectional, meaning that they must be addressed in both directions along a relationship.
A. True
B. False
A
B. False
16
Q
When the specific cardinalities are not included on the diagram in Crow's Foot notation, cardinality is implied by the use of \_\_\_\_\_. A. symbols B. attributes C. images D. tables
A
A. Symbols
17
Q
A weak entity has a primary key that is partially or totally derived from the parent entity in the relationship.
A. True
B. False
A
A. True
18
Q
In the entity relationship diagram (ERD), cardinality is indicated using the \_\_\_\_\_ notation, where max is the maximum number of associated entities and min represents the minimum number of associated entities.
A. (max, min)
B. (min, max)
C. [min ... max]
D. {min|max}
A
B. (min, max)
19
Q
The Crow’s foot symbol with two vertical parallel lines indicates \_\_\_\_\_ cardinality. A. (0,N) B. (1,N) C. (1,1) D. (0,1)
A
C. (1,1)
20
Q
The decision to store \_\_\_\_\_ attributes in database tables depends on the processing requirements and the constraints placed on a particular application. A. multivalued B. derived C. single-valued D. composite
A
b. derived
21
Q
A \_\_\_\_\_ entity has a primary key that is partially or totally derived from the parent entity in the relationship. A. strong B. weak C. business D. child
A
B. weak
22
Q
When using the Crow's Foot notation, the associative entity is indicated by \_\_\_\_\_ relationship lines between the parents and the associative entity. A. dotted B. double C. triple D. solid
A
D. Solid
23
Q
Composite attributes make it easier to facilitate detailed queries.
A. True
B. False
A
B. False
24
Q
To implement a small database, a database designer must know the “1” and the “M” sides of each relationship and whether the relationships are mandatory or optional.
A. True
B. False
A
A. True
25
Connectivities and cardinalities are established by concise statements known as business rules.
A. True
B. False
A. True
26
To simplify the conceptual design, most higher-order relationships are decomposed into appropriate equivalent _____ relationships whenever possible.
B. Binary
27
```
An entity is said to be _____-dependent if it can exist in the database only when it is associated with another related entity occurrence.
A. existence
B. relationship
C. business
D. data
```
A. existence
28
```
A _____ attribute can be further subdivided to yield additional attributes.
A. composite
B. simple
C. single-valued
D. multivalued
```
A. composite
29
```
The entity relationship model uses the associative entity to represent a(n) _____ relationship between two or more entities.
A. M:N
B. 1:M
C. N:1
D. M:1
```
A. M:N
30
```
If an employee within an EMPLOYEE entity has a relationship with itself, that relationship is known as a _____ relationship.
A. self
B. self-referring
C. looping
D. recursive
```
D. recursive
31
The entity supertype contains common characteristics, and the entity subtypes each contain their own unique characteristics.
A. True
B. False
A. True
32
The relationships depicted within the specialization hierarchy are sometimes described in terms of “is-a” relationships.
A. True
B. False
A. True
33
One important inheritance characteristic is that all entity subtypes inherit their primary key attribute from their supertype.
A. True
B. False
A. True
34
At the implementation level, the supertype and its subtype(s) depicted in the specialization hierarchy maintain a 1:1 relationship.
A. True
B. False
A. True
35
In specialization hierarchies with multiple levels of supertype and subtypes, a lower-level subtype can inherit only a few of the attributes and relationships from its upper-level supertypes.
A. True
B. False
B. False
36
An entity supertype can have disjoint or overlapping entity subtypes.
A. True
B. False
A. True
37
Overlapping subtypes are subtypes that contain a unique subset of the supertype entity set.
A. True
B. False
B. False
38
The completeness constraint can be partial or total.
A. True
B. False
A. True
39
An entity cluster is a "virtual" entity type used to represent multiple entities and relationships in the ERD.
A. True
B. False
A. True
40
```
The extended entity relationship model (EERM) is sometimes referred to as the _____.
A. enclosed entity relationship model
B. enhanced entity relationship model
C. entity clustering relationship model
D. extended entity relationship diagram
```
B. enhanced entity relationship model
41
```
The _____ depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).
A. subtype discriminator
B. inheritance
C. specialization hierarchy
D. entity supertype
```
C. specialization hierarchy
42
```
A specialization hierarchy can have _____ level(s) of supertype/subtype relationships.
A. zero
B. only one
C. one or many
D. many
```
D. Many
43
```
One important inheritance characteristic is that all entity subtypes inherit their _____ key attribute from their supertype.
A. primary
B. natural
C. foreign
D. surrogate
```
A. primary
44
```
A(n) _____ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.
A. subtype discriminator
B. inheritance discriminator
C. specialization hierarchy
D. entity supertype
```
A. subtype discriminator
45
Which of the following is a specialization hierarchy disjoint constraint scenario in case of partial completeness?
A. Subtype discriminator can be null.
B. Subtype discriminator cannot be null.
C. Each supertype occurrence is a member of only one subtype.
D. Each supertype occurrence is a member of at least one subtype.
A. Subtype discriminator can be null.
46
```
Nonoverlapping subtypes are subtypes that contain a(n) _____ subset of the supertype entity set.
A. entity
B. subtypes
C. unique
D. nonunique
```
C. unique
47
A total completeness constraint is represented by a _____.
A. smaller circle inside a bigger circle
B. rhombus inside a circle
C. double horizontal line under a circle
D. single horizontal line above a circle
C. double horizontal line under a cricle
48
```
In the context of total completeness, in a(n) _____, every supertype occurrence is a member of only one subtype.
A. foreign key constraint
B. nonunique constraint
C. overlapping constraint
D. disjoint constraint
```
D. disjoint constraint
49
```
_____ is the bottom-up process of identifying a higher-level, more generic entity supertype from lower-level entity subtypes.
A. Specialization
B. Generalization
C. Normalization
D. Total completeness
```
B. Generalization
50
```
The purpose of an entity _____ is to simplify an entity-relationship diagram (ERD) and thus enhance its readability.
A. constraint
B. cluster
C. interface
D. discriminator
```
B. cluster
51
```
An entity cluster is formed by combining multiple interrelated entities into _____.
A. a single abstract entity object
B. multiple abstract entity objects
C. a single entity object
D. multiple entity objects
```
A. a single abstract entity object
52
```
The most important characteristic of an entity is its _____ key, used to uniquely identify each entity instance.
A. primary
B. natural
C. foreign
D. surrogate
```
A. primary
53
```
A _____ key is a real-world, generally accepted identifier used to uniquely identify real-world objects.
A. primary
B. natural
C. foreign
D. surrogate
```
B. Natural
54
```
If one exists, a data modeler uses a _____ as the primary key of the entity being modeled.
A. foreign key
B. combination key
C. surrogate key
D. natural identifier
```
D. natural identifier
55
```
A _____ is a primary key created by a database designer to simplify the identification of entity instances.
A. composite key
B. compound key
C. natural key
D. surrogate key
```
D. surrogate key
56
```
Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed only once in the _____ relationship.
A. 0:1
B. 1:1
C. 1:M
D. M:N
```
D. M:N
57
```
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 violation.
A. unique values
B. nonintelligent
C. preferably single-attribute
D. security-compliant
```
D. security-compliant
58
The “_____” characteristic of a primary key states that the primary key must uniquely identify each entity instance, must be able to guarantee unique values, and must not contain nulls.
A. unique values
59
According to the “preferably single-attribute” characteristic of a primary key, the primary key:
A. must be able to guarantee unique attribute values.
B. should have the minimum number of attributes possible.
C. should have embedded semantic meaning associated with each attribute.
D. must be composed of attributes that are free from security risks or violations.
B. should have the minimum number of attributes possible
60
```
The “_____” characteristic of a primary key states that the primary key should not have embedded semantic meaning.
A. unique values
B. nonintelligent
C. preferably single-attribute
D. security-compliant
```
B. nonintelligent
61
Data redundancy produces data anomalies.
True
False
True
62
Relational models view data as part of a table or collection of tables in which all key values
must be identified.
True
False
True
63
A dependency of one nonprime attribute on another nonprime attribute is a partial
dependency.
True
False
False
64
Dependencies that are based on only a part of a composite primary key are called transitive
dependencies.
True
False
False
65
In the context of partial dependencies, data redundancies occur because every row entry
requires duplication of data.
True
False
True
66
It is possible for a table in 2NF to exhibit transitive dependency, where the primary key may
rely on one or more nonprime attributes to functionally determine other nonprime attributes.
True
False
True
67
Data stored at their highest level of granularity are said to be atomic data.
True
False
False
68
A table is in BCNF if every determinant in the table is a foreign key.
True
False
False
69
Normalization represents a micro view of the entities within the ERD.
True
False
True
70
A good relational DBMS excels at managing denormalized relations.
True
False
False
71
Normalization purity is often easy to sustain in the modern database environment.
True
False
False
72
Attributes should clearly define participation, connectivity, and document cardinality.
True
False
False
73
```
From a structural point of view, 3NF is better than _____.
A. 4N F
B. 2N F
C. 5N F
D. 6N F
```
B. 2N F
74
```
n attribute that is part of a key is known as a(n) _____ attribute.
A. important
B. nonprime
C. prime
D. entity
```
C. prime
75
```
Data redundancy produces _____.
A. slower lookups
B. robust design
C. efficient storage use
D. data integrity problems
```
D. data integrity problems
76
```
Some very specialized applications may require normalization beyond the _____.
A. 1NF
B. 2NF
C. 3NF
D. 4NF
```
D. 4NF
77
```
A table that has all key attributes defined, has no repeating groups, and all its attributes are dependent on the primary key is said to be in _____.
A. 1NF
B. 2NF
C. 3NF
D. 4NF
```
A. 1NF
78
```
A(n) _____ exists when there are functional dependencies such that Y is functionally dependent on X, Z is functionally dependent on Y, and X is the primary key.
A. partial dependency
B. repeating group
C. atomic attribute
D. transitive dependency
```
D. transitive dependency
79
```
A relational table must not contain a(n) _____.
A. entity
B. attribute
C. relationship
D. repeating group
```
D. repeating group
80
```
Dependencies based on only a part of a composite primary key are known as _____ dependencies.
A. primary
B. partial
C. incomplete
D. composite
```
B. partial
81
```
A table that is in 2NF and contains no transitive dependencies is said to be in _____.
A. 1NF
B. 2NF
C. 3NF
D. 4NF
```
C. 3NF
82
```
An atomic attribute _____.
A. cannot exist in a relational table
B. cannot be further subdivided
C. displays multiplicity
D. is always chosen to be a foreign key
```
b. cannot be further subdivided
83
Granularity refers to _____.
A. the size of a table
B. the level of detail represented by the values in a table's row
C. the number of attributes represented in a table
D. the number of rows in a table
B. the level of detail represented by the values in a table's row
84
```
In a real-world environment, we must strike a balance between design integrity and _____.
A. robustness
B. flexibility
C. uniqueness
D. ease of use
```
B. flexibility
85
```
To generate a surrogate key, Microsoft Access uses a(n) _____ data type.
A. character
B. sequence
C. AutoNumber
D. identity
```
C. AutoNumber
86
```
BCNF can be violated only if the table contains more than one _____ key.
A. primary
B. candidate
C. foreign
D. secondary
```
B. candidate
87
```
In a _____ situation, one key determines multiple values of two other attributes and those attributes are independent of each other.
A. multivalued dependency
B. transitive dependency
C. partial dependency
D. functional dependency
```
A. multivalued dependency
88
A table is in 4NF if it is in 3NF, and _____.
A. all attributes must be dependent on the primary key and must be dependent on each other
B. all attributes are unrelated
C. it has no multivalued dependencies
D. no column contains the same values
C. It has no multivalued dependencies
89
```
An example of denormalization is using a _____ denormalized table to hold report data. This is required when creating a tabular report in which the columns represent data that are stored in the table as rows.
A. transitive
B. 3NF
C. component
D. temporary
```
D. temporary
90
```
Data warehouse routinely uses _____ structures in its complex, multilevel, multisource data environment.
A. 1NF
B. 2NF
C. 3NF
D. 4NF
```
B. 2NF
91
The COMMIT command does not permanently save all changes. In order to do that, you must use SAVE.
A. True
B. False
B. False
92
All SQL commands must be issued on a single line.
A. True
B. False
B. False
93
An alias cannot be used when a table is required to be joined to itself in a recursive query.
A. True
B. False
B. False
94
You can select partial table contents by naming the desired fields and by placing restrictions on the rows to be included in the output.
A. True
B. False
A. True
95
String comparisons are made from left to right.
A. True
B. False
A. True
96
Date procedures are often more software-specific than other SQL procedures.
A. True
B. False
A. True
97
SQL allows the use of logical restrictions on its inquiries such as OR, AND, and NOT.
A. True
B. False
A. True
98
You cannot insert a row containing a null attribute value using SQL.
A. True
B. False
B. False
99
The conditional LIKE must be used in conjunction with wildcard characters.
A. True
B. False
A. True
100
Most SQL implementations yield case-insensitive searches.
A. True
B. False
B. False
101
The COUNT function is designed to tally the number of non-null "values" of an attribute, and is often used in conjunction with the DISTINCT clause.
A. True
B. False
A. True
102
The SQL data manipulation command HAVING:
A. restricts the selection of rows based on a conditional expression.
B. restricts the selection of grouped rows based on a condition.
C. modifies an attribute’s values in one or more table’s rows.
D. groups the selected rows based on one or more attributes.
B. restricts the selection of grouped rows based on a condition
103
```
The SQL command that allows a user to permanently save data changes is _____.
A. INSERT
B. SELECT
C. COMMIT
D. UPDATE
```
C. Commit
104
```
The _____ command defines a default value for a column when no value is given.
A. CHECK
B. UNIQUE
C. NOT NULL
D. DEFAULT
```
D. Default
105
```
The _____ command restricts the selection of grouped rows based on a condition.
A. DISPLAY
B. HAVING
C. FROM
D. CONVERT
```
B. Having
106
```
A(n) _____ query specifies which data should be retrieved and how it should be filtered, aggregated, and displayed.
A. INSERT
B. SELECT
C. COMMIT
D. UPDATE
```
B. Select
107
```
A(n) _____ is an alternate name given to a column or table in any SQL statement.
A. alias
B. data type
C. stored function
D. trigger
```
A. Alias
108
```
According to the rules of precedence, which of the following computations should be completed first?
A. Additions and subtractions
B. Multiplications and divisions
C. Operations within parentheses
D. Power operations
```
c. Operations within parentheses
109
```
When using a(n) _____ join, only rows from the tables that match on a common value are returned.
A. full
B. outer
C. inner
D. set
```
C. Inner
110
```
A(n) _____ join will select only the rows with matching values in the common attribute(s).
A. natural
B. outer
C. full
D. cross
```
A. Natural
111
```
A(n) _____ join returns not only the rows matching the join condition (that is, rows with matching values in the common columns) but also the rows with unmatched values.
A. outer
B. inner
C. equi-
D. cross
```
a. outer
112
The syntax for a left outer join is _____.
A. SELECT column-list
FROM table1 OUTER JOIN table2 LEFT
WHERE join-condition
B. SELECT column-list
FROM table1 LEFT [OUTER] JOIN table2
ON join-condition
C. SELECT column-list
WHERE LEFT table1 = table
D. SELECT column-list
FROM table1 LEFT table2 [JOIN]
WHERE join-condition
B.SELECT column-list
FROM table1 LEFT [OUTER] JOIN table2
ON join-condition
113
```
A(n) _____ join performs a relational product (also known as the Cartesian product) of two tables.
A. full
B. cross
C. natural
D. equi-
```
B. cross
114
```
How many rows would be returned from a cross join of tables A and B, if A contains 8 rows and B contains 18?
A. 8
B. 18
C. 26
D. 144
```
D. 144
115
```
Which comparison operator indicates a value is not equal?
A. <
B. <=
C. >=
D. <>
```
D. <>
116
What type of command does this SQL statement use?
SELECT P_CODE, P_DESCRIPT, P_PRICE_V_NAME
FROM PRODUCT, VENDOR
WHERE PRODUCT.V_CODE=VENDOR. V_CODE
A. set operator
B. natural join
C. "old-style" join
D. procedural statement
C. "old-style" join
117
```
The special operator used to check whether an attribute value is within a range of values is _____.
A. BETWEEN
B. NULL
C. LIKE
D. IN
```
A. Between
118
```
A(n) _____ is a query that is embedded (or nested) inside another query.
A. alias
B. operator
C. subquery
D. view
```
C. subquery
119
```
In subquery terminology, the first query in the SQL statement is known as the _____ query.
A. outer
B. left
C. inner
D. base
```
A. outer
120
```
The special operator used to check whether a subquery returns any rows is _____.
A. BETWEEN
B. EXISTS
C. LIKE
D. IN
```
B. exists
