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Data > Week 4 > Flashcards

Week 4 Flashcards

1
Q

An ____ is a group of objects with the same properties, which are identified by the enterprise as having an independent existence.

A

entity type

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2
Q

An _____ is a uniquely identifiable object of an entity type.

A

entity occurrence

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3
Q

A ____ is a set of meaningful associations among entity types.

A

relationship type

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4
Q

A ______ is a uniquely identifiable association, which includes one occurrence from each participating entity type.

A

relationship occurrence

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5
Q

The _____ is the number of participating entity types in a relationship.

A

degree of a relationship type

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6
Q

A ____ is a relationship type where the same entity type participates more than once in
different roles.

A

recursive relationship

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7
Q

An ____ is a property of an entity or a relationship type.

A

attribute

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8
Q

An ______ is the set of allowable values for one or more attributes.

A

attribute domain

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9
Q

A ___ is composed of a single component with an independent existence.

A

simple attribute

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10
Q

A ______ is composed of multiple components each with an independent existence.

A

composite attribute

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11
Q

A _____ holds a single value for each occurrence of an entity type.

A

single-valued attribute

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12
Q

A _____ holds multiple values for each occurrence of an entity type.

A

multi-valued attribute

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13
Q

A ____ represents a value that is derivable from the value of a related attribute or set of attributes,
not necessarily in the same entity.

A

derived attribute

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14
Q

A ____ is the minimal set of attributes that uniquely identifies each occurrence of an entity type.

A

candidate key

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15
Q

A _____ is the candidate key that is selected to uniquely identify each occurrence of an entity type.

A

primary key

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16
Q

A _____ is a candidate key that consists of two or more attributes.

A

composite key

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17
Q

A _____ type is not existence-dependent on some other entity type.

A

strong entity

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18
Q

A _____ type is existence-
dependent on some other entity type.

A

weak entity

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19
Q

____ is the number (or range) of possible occurrences of an entity type that may relate to a single
occurrence of an associated entity type through a particular relationship.

A

Multiplicity

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20
Q

_______ is the number (or range) of possible occurrences of an entity type
in an n-ary relationship when the other (n–l) values are fixed.

A

Multiplicity for a complex relationship

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21
Q

_____ describes the maximum number of possible relationship occurrences for an entity participating in a
given relationship type.

A

Cardinality

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22
Q

____ determines whether all or only some entity occurrences participate in a given relationship.

A

Participation

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23
Q

A _____ exists where a model represents a relationship between entity types, but the pathway between certain
entity occurrences is ambiguous.

A

fan trap

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24
Q

A ___ exists where a model suggests the existence of a relationship between entity types, but the
pathway does not exist between certain entity occurrences.

A

chasm trap

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25
Q

A ____ is an entity type that includes one or more distinct subgroupings of its occurrences,
which require to be represented in a data model.

A

superclass

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26
Q

A ____ is a distinct subgrouping
of occurrences of an entity type, which require to be represented in a data model.

A

subclass

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27
Q

_____ is the process of maximizing the differences between members of an entity by identifying their distinguishing features.

A

Specialization

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28
Q

______ is the process of minimizing the differences between entities by identifying their common features.

A

Generalization

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29
Q

There are two constraints that may apply to a specialization/generalization called ____ and ___.

A

participation constraints and disjoint constraints

30
Q

A _____ determines whether every member in the superclass must participate as a member of a subclass.

A

participation constraint

31
Q

A ______ describes the relationship between members of the subclasses and indicates whether it is possible for a member of a superclass to be a member of one, or
more than one, subclass.

A

disjoint constraint

32
Q

______ represents a “has-a” or “is-part-of ” relationship between entity types, where one represents the “whole” and the other the “part.”

A

Aggregation

33
Q

______ is a specific form of aggregation that represents an association between entities, where there is
a strong ownership and coincidental lifetime between the “whole” and the “part.”

A

Composition

34
Q

_____ is a technique for producing a set of relations with desirable properties, given the data requirements
of an enterprise.

A

Normalization

35
Q

______ is a formal method that can be used to identify relations based on their
keys and the functional dependencies among their attributes.

A

Normalization

36
Q

Relations with data redundancy suffer from ______, which can be classified as insertion, deletion,
and modification anomalies.

A

update anomalies

37
Q

One of the main concepts associated with normalization is _____ , which describes the
relationship between attributes in a relation. For example, if A and B are attributes of relation R, B is functionally dependent on A (denoted A ® B), if each value of A is associated with exactly one value of B. (A and B may each consist of one or more attributes.)

A

functional dependency

38
Q

The ____ of a functional dependency refers to the attribute, or group of attributes, on the left-hand
side of the arrow

A

determinant

39
Q

The main characteristics of functional dependencies that we use for normalization have a one-to-one relationship between attribute(s) on the left-hand and right-hand sides of the dependency, hold for all time, and are fully functionally dependent.

A

true

40
Q

_____ is a table that contains one or more repeating groups.

A

Unnormalized Form (UNF)

41
Q

_____ is a relation in which the intersection of each row and column contains one and
only one value.

A

First Normal Form (1NF)

42
Q

______ is a relation that is in first normal form and every non-primary-key attribute
is fully functionally dependent on the primary key

A

Second Normal Form (2NF)

43
Q

______ indicates that if A and B are
attributes of a relation, B is fully functionally dependent on A if B is functionally dependent on A but not on any
proper subset of A.

A

Full functional dependency

44
Q

______ is a relation that is in first and second normal form in which no non-primary- key
attribute is transitively dependent on the primary key.

A

Third Normal Form (3NF)

45
Q

_____ is a condition where A, B, and C
are attributes of a relation such that if A ® B and B ® C, then C is transitively dependent on A via B (provided
that A is not functionally dependent on B or C).

A

Transitive dependency

46
Q

_____ is a relation that is in first normal form and every
non-candidate-key attribute is fully functionally dependent on any candidate key. In this definition, a candidate-key attribute is part of any candidate key.

A

General definition for Second Normal Form (2NF)

47
Q

______ is a relation that is in first and second normal form in which no non-candidate-key attribute is transitively dependent on any candidate key. In this definition, a candidate-key attribute is part of any candidate key.

A

General definition for Third Normal Form (3NF)

48
Q

____ is a nonprocedural language consisting of standard English words such as SELECT, INSERT, and DELETE that
can be used by professionals and non-professionals alike. It is both the formal and de facto standard language for defining and manipulating relational databases.

A

SQL

49
Q

The _____ statement is the most important statement in the language and is used to express a query. It
combines the three fundamental relational algebra operations of Selection, Projection, and Join.

A

SELECT

50
Q

Every _____ statement produces a query result table consisting of one or more columns and zero or more rows.

A

SELECT

51
Q

The _____ clause identifies the columns and/or calculated data to appear in the result table. All column names that appear in the _____ clause must have their corresponding tables or views listed in the FROM clause.

A

SELECT

52
Q

The SELECT clause identifies the columns and/or calculated data to appear in the result table. All column names that appear in the SELECT clause must have their corresponding tables or views listed in the ______ clause.

A

FROM

53
Q

The ______ clause selects rows to be included in the result table by applying a search condition to the rows
of the named table(s).

A

WHERE

54
Q

The _____ clause allows the result table to be sorted on the values in one or more columns. Each column can be sorted in ascending or descending order. If specified, the _____ clause must be the last clause in the SELECT statement.

A

ORDER BY

55
Q

The ORDER BY clause allows the result table to be sorted on the values in one or more
columns. Each column can be sorted in ascending or descending order. If specified, the ORDER BY clause must be the last clause in the ____ statement.

A

SELECT

56
Q

SQL supports five aggregate functions that take an entire column as an argument and compute a single value as the result.

A

(COUNT, SUM, AVG, MIN, and MAX)

57
Q

It is illegal to mix aggregate functions with column names in a SELECT clause, unless the GROUP BY clause is used.

A

TRUE

58
Q

The ______ clause allows summary information to be included in the result table. Rows that have the same
value for one or more columns can be grouped together and treated as a unit for using the aggregate functions. In this case, the aggregate functions take each group as an argument and compute a single value for each group as the result.

A

GROUP BY

59
Q

The _____ clause acts as a WHERE clause for groups, restricting the groups that appear in the
final result table. However, unlike the WHERE clause, the ______ clause can include aggregate functions.

A

HAVING

60
Q

A _____ is a complete SELECT statement embedded in another query. A ______ may appear within the
WHERE or HAVING clauses of an outer SELECT statement, where it is called a ___ OR ____

A

subselect

subquery or nested query.

61
Q

Conceptually, a subquery produces a temporary table whose contents can be accessed by the outer query. A
subquery can be embedded in another subquery.

A

true

62
Q

There are three types of subquery:

A

scalar, row, and table.

63
Q

A ______ returns a single column and a single
row, that is, a single value. In principle, a _____ can be used whenever a single value is needed.

A

scalar subquery

64
Q

A _____ returns multiple columns, but only a single row. A _____can be used whenever a row value constructor
is needed, typically in predicates.

A

row subquery

65
Q

A ______ returns one or more columns and multiple rows. A ____ can be used whenever a table is needed; for example, as an operand for the IN predicate.

A

table subquery

66
Q

If the columns of the result table come from more than one table, a ___ must be used, by specifying more than
one table in the FROM clause and typically including a WHERE clause to specify the ____ column(s).

A

join

67
Q

The ISO standard allows _____ to be defined.

A

Outer joins

68
Q

It also allows the set operations of Union, Intersection, and Difference to be used with the ___, ____,and ____ commands.

A

UNION, INTERSECT, and EXCEPT

69
Q

As well as SELECT, the SQL DML includes the _____ statement to insert a single row of data into a
named table or to insert an arbitrary number of rows from one or more other tables using a _____;

A

INSERT

subselect

70
Q

the ____ statement to update one or more values in a specified column or columns of a named table;

A

UPDATE

71
Q

the _____ statement to delete one or more rows from a named table.

A

DELETE

Data (4 decks)

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