Infoman Reviewer

Question 1

Is used extensively in mathematics to provide a framework, can be verified as either true or false

Answer 1

Predicate Logic

Question 2

is a part of mathematical science that deals with
sets, or groups of things, and is used as the basis for data
manipulation in the relational model

Answer 2

Set Theory

Question 3

relational model has three (3) components

Answer 3

1. A logical data structure represented by relations
2. A set of integrity rules to enforce that the data is consistent
   and remains consistent over time
3. A set of operations that defines how data is manipulated

Question 4

is as a two-dimensional structure composed of
rows and columns

Answer 4

table (relation)

Question 5

represents data about an entity.

Answer 5

e row (tuple

Question 6

Each table column represents an a

Answer 6

attribute,

Question 7

Each
column has a specific range of values known as the attribute
.

Answer 7

domain

Question 8

is an attribute or group of attributes that determines the
values of other attributes. For example, an invoice number identifies
all of the invoice attributes, such as the invoice date and the
customer name

Answer 8

key

Question 9

is the state in which knowing the value of an
attribute makes it possible to determine the value of another. It is
based on the relationships among the attributes.

Answer 9

Determination

Question 10

means that the value of one or more
attributes determines the value of one or more other attributes.

Answer 10

Functional dependence

Question 11

The attribute whose value determines another is called the

Answer 11

determinant or the key.

Question 12

The attribute whose value is determined
by the other attribute is called the

Answer 12

dependent

Question 13

is a key that is composed of more than one
attribute.

Answer 13

composite key

Question 14

An attribute or combination of attributes that
uniquely identifies any row in the table

Answer 14

Superkey

Question 15

A superkey without any unnecessary attributes

Answer 15

Candidate Key

Question 16

A candidate key selected to uniquely identify all
other attribute values in any given row; cannot
contain null entries

Answer 16

Primary Key

Question 17

An attribute or combination of attributes in one table
whose values must either match the primary key in
another table or be null.

Answer 17

Foreign Key

Question 18

An attribute or combination of attributes used strictly
for data retrieval purposes.

Answer 18

Secondary Key

Question 19

Integrity Rules

Answer 19

An entity integrity is the condition in which each row in a table has
its own unique identity.
* A referential integrity is the conditional in which every reference to
an entity instance by another entity instance is valid.
* Integrity rules are followed to maintain a good database design

Question 20

To avoid nulls, special codes called ______ are used to indicate the
absence of some value.

Answer 20

flags

Question 21

is a set of mathematical principles that form the
basis for manipulating relational table contents.

Answer 21

Relational algebra

Question 22

The use of relational algebra operators on existing relations (tables)
produces new relations is called

Answer 22

closure

Question 23

The condition to be evaluated is also known as

Answer 23

predicate

Question 24

Retrieves a subset of rows

Answer 24

SELECT σ
Syntax σ CONDITION (TABLE)

Question 25

Retrieves a subset of columns π Syntax π COLUMNS (TABLE

Answer 25

PROJECT π Syntax π COLUMNS (TABLE

Question 26

Merges two union-compatible tables into a new table, dropping the duplicate rows

Answer 26

UNION Syntax TABLE1 ∪ TABLE2

Question 27

Retrieves rows that are common to two union-compatible tables

Answer 27

INTERSECT ∩ Syntax TABLE1 ∩ TABLE2

Question 28

Retrieves rows from one table that are not found in another union-compatible table

Answer 28

DIFFERENCE

Question 29

Retrieves possible pairs of rows from two tables (Cartesian Product)

Answer 29

PRODUCT x Syntax TABLE1 x TABLE2

Question 30

Retrieves rows from two tables based on criteria (Ex. Rows with common values in their common attributes)

Answer 30

JOIN ⨝ Syntax TABLE1 ⨝ TABLE2

Question 31

Retrieves values ÷

Answer 31

DIVIDE ÷ Syntax TABLE1 ÷ TABLE2

Question 32

is a data model that describes relationships among entities at the conceptual level with the help of ER diagrams

Answer 32

Entity Relationship Model (ERM)

Question 33

is a diagram that depicts an entity relationship model’s entities, attributes, and relations.

Answer 33

Entity Relationship Diagram (ERD)

Question 34

Each row in the relational table is known as an

Answer 34

entity instance or entity occurrence

Question 35

A collection of similar entities is known as an

Answer 35

entity set

Question 36

describe associations among data.

Answer 36

Relationships

Question 37

Relationships are represented by a diamond connected to the related entities through a relationship line. The relationship name is written inside the diamond.

Answer 37

Chen notation:

Question 38

Entities are connected by lines, and symbols at either end describe the cardinality of the relationship between the entities

Answer 38

Crow's Foot notation:

Question 39

is raw data in its original state. It might contain redundant data, multivalued data, and/or other data anomalies.

Answer 39

unnormalized data

Question 40

is a process that assigns attributes to entities so that data redundancies are reduced or eliminated

Answer 40

Normalization

Question 41

is an undesirable consequence of a data modification

Answer 41

data anomaly

Question 42

* Objectives of normalization:

Answer 42

o Each table/relation represents a single subject. o Each row/column intersection contains only one value and not a group of values. o No data item will be unnecessarily stored in more than one table. o All nonprime attributes (not part of a key) in a table are dependent on the primary key. o Each table has no insertion, update, or deletion anomalies.

Question 43

Each rule in database normalization is called a

Answer 43

normal form

Question 44

There are no repeating groups and the primary key is identified.

Answer 44

First normal form (1NF)

Question 45

1NF and all the columns depend on the table’s primary key. Third normal form

Answer 45

Second normal form (2NF)

Question 46

2NF and there are no non-key attributes determined by another nonkey attribute.

Answer 46

Third normal form (3NF)

Question 47

Every determinant is a candidate key (special case of 3NF)

Answer 47

Boyce-Codd normal form (BCNF)

Question 48

3NF and no independent multivalued dependencies

Answer 48

Fourth normal form (4NF)

Question 49

considered the highest level necessary for most applications.

Answer 49

3NF