Week 4

Question 1

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

Answer 1

entity type

Question 2

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

Answer 2

entity occurrence

Question 3

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

Answer 3

relationship type

Question 4

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

Answer 4

relationship occurrence

Question 5

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

Answer 5

degree of a relationship type

Question 6

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

Answer 6

recursive relationship

Question 7

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

Answer 7

attribute

Question 8

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

Answer 8

attribute domain

Question 9

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

Answer 9

simple attribute

Question 10

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

Answer 10

composite attribute

Question 11

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

Answer 11

single-valued attribute

Question 12

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

Answer 12

multi-valued attribute

Question 13

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

Answer 13

derived attribute

Question 14

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

Answer 14

candidate key

Question 15

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

Answer 15

primary key

Question 16

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

Answer 16

composite key

Question 17

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

Answer 17

strong entity

Question 18

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

Answer 18

weak entity

Question 19

____ 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.

Answer 19

Multiplicity

Question 20

_______ 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.

Answer 20

Multiplicity for a complex relationship

Question 21

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

Answer 21

Cardinality

Question 22

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

Answer 22

Participation

Question 23

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

Answer 23

fan trap

Question 24

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

Answer 24

chasm trap

Question 25

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

Answer 25

superclass

Question 26

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

Answer 26

subclass

Question 27

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

Answer 27

Specialization

Question 28

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

Answer 28

Generalization

Question 29

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

Answer 29

participation constraints and disjoint constraints

Question 30

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

Answer 30

participation constraint

Question 31

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.

Answer 31

disjoint constraint

Question 32

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

Answer 32

Aggregation

Question 33

______ 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.”

Answer 33

Composition

Question 34

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

Answer 34

Normalization

Question 35

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

Answer 35

Normalization

Question 36

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

Answer 36

update anomalies

Question 37

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.)

Answer 37

functional dependency

Question 38

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

Answer 38

determinant

Question 39

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.

Answer 39

true

Question 40

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

Answer 40

Unnormalized Form (UNF)

Question 41

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

Answer 41

First Normal Form (1NF)

Question 42

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

Answer 42

Second Normal Form (2NF)

Question 43

______ 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.

Answer 43

Full functional dependency

Question 44

______ 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.

Answer 44

Third Normal Form (3NF)

Question 45

_____ 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).

Answer 45

Transitive dependency

Question 46

_____ 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.

Answer 46

General definition for Second Normal Form (2NF)

Question 47

______ 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.

Answer 47

General definition for Third Normal Form (3NF)

Question 48

____ 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.

Answer 48

SQL

Question 49

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.

Answer 49

SELECT

Question 50

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

Answer 50

SELECT

Question 51

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.

Answer 51

SELECT

Question 52

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.

Answer 52

FROM

Question 53

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

Answer 53

WHERE

Question 54

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.

Answer 54

ORDER BY

Question 55

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.

Answer 55

SELECT

Question 56

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

Answer 56

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

Question 57

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

Answer 57

TRUE

Question 58

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.

Answer 58

GROUP BY

Question 59

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.

Answer 59

HAVING

Question 60

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 ____

Answer 60

subselect subquery or nested query.

Question 61

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

Answer 61

true

Question 62

There are three types of subquery:

Answer 62

scalar, row, and table.

Question 63

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.

Answer 63

scalar subquery

Question 64

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

Answer 64

row subquery

Question 65

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.

Answer 65

table subquery

Question 66

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).

Answer 66

join

Question 67

The ISO standard allows _____ to be defined.

Answer 67

Outer joins

Question 68

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

Answer 68

UNION, INTERSECT, and EXCEPT

Question 69

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 _____;

Answer 69

INSERT subselect

Question 70

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

Answer 70

UPDATE

Question 71

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

Answer 71

DELETE