Chapter 2. Data Models

Question 1

It is the first step in designing a database, refers to the process of creating a specific data model for a determined problem domain

Answer 1

Data Modeling

Question 2

It is a relatively simple representation, usually graphical, of more complex real-world data structures

Answer 2

Data Model

Question 3

It is a person, place, thing, or event about which data can be stored

Answer 3

Entity

Question 4

It is a characteristic of an entity or object. An attribute has a name and a data type

Answer 4

Attribute

Question 5

An association between entities

Answer 5

Relationship

Question 6

Types of relationships

Answer 6

• One-to-Many Relationship
• Many-to-One Relationship
• One-to-One Relationship

Question 7

A restriction placed on data, usually expressed in the form of rules.

Answer 7

Constraint

Question 8

A description of a policy, procedure, or principle within an organization.

Answer 8

Business Rule

Question 9

To properly identify the type of relationship, you should consider that relationships are __

Answer 9

Bidirectional

Question 10

Entity names should be descriptive of the objects in the business environment and use terminology that is familiar to the users.

Answer 10

Naming Conventions

Question 11

An attribute name should also be descriptive of the data represented by that attribute.

Answer 11

Naming Convention

Question 12

It is also a good practice to prefix the name of an attribute with the name or abbreviation of the entity in which it occurs.

Answer 12

Naming Conventions

Question 13

Is based on mathematical set theory and represents data as independent relations.

Answer 13

Relational Model

Question 14

Is conceptually represented as a two-dimensional structure of intersecting rows and columns.

Answer 14

Each relation

Question 15

The relations are related to each other through the sharing of common ___

Answer 15

Entity Characteristics

Question 16

A logical construct perceived to be a two-dimensional structure composed of intersecting rows (entities) and columns (attributes) that represents an entity set in the relational model.

Answer 16

Table (Relation)

Question 17

In the relational model, a table row

Answer 17

Tuple

Question 18

Each ___ represents an attribute

Answer 18

Column

Question 19

The relational model also describes a precise set of data manipulation constructs based on advanced mathematical concepts

Answer 19

Table

Question 20

Tables are related to each other through the sharing of a common ___

Answer 20

Attribute

Question 21

A collection of programs that manages a relational database. The ___ software translates a user’s logical requests (queries) into commands that physically locate and retrieve the requested data.

Answer 21

Relational Database Management System (RDBMS)

Question 22

It is a representation of the relational database’s entities, the attributes within those entities, and the relationships between those entities

Answer 22

Relational Diagram

Question 23

A data model that describes relationships (1:1, 1:M, and M:N) among entities at the conceptual level with the help of ER diagrams.

Answer 23

Entity relationship (ER) model (ERM)

Question 24

A diagram that depicts an entity relationship model’s entities, attributes, and relations

Answer 24

Entity Relationship Diagram (ERD)

Question 25

Defined as anything about which data will be collected and stored

Answer 25

Entity

Question 26

An entity is represented in the ERD by a rectangle, also known as an ___

Answer 26

Entity Box

Question 27

The name of the entity, a noun, is written in the center of the ____

Answer 27

Rectangle

Question 28

The entity name is generally written in ___

Answer 28

Capital Letters and in Singular Form

Question 29

Each entity consists of a ___ that describes particular characteristics of the entity.

Answer 29

Set of attributes

Question 30

It describes associations among data. Most relationships describe associations between two entities.

Answer 30

Relationships

Question 31

ER Notations

Answer 31

- Chen Notation - Crow's Foot - Class Diagram Notation

Question 32

The application programmer’s view of the data environment.

Answer 32

External Model

Question 33

Works with a data subset of the global database schema.

Answer 33

External Model

Question 34

The specific representation of an external view; the end user’s view of the data environment

Answer 34

External Schema

Question 35

It represents a global view of the entire database by the entire organization.

Answer 35

Conceptual Model

Question 36

Integrates all external views (entities, relationships, constraints, and processes) into a single global view of the data in the enterprise

Answer 36

Conceptual Model

Question 37

A representation of the conceptual model, usually expressed graphically

Answer 37

Conceptual Schema

Question 38

A property of any model or application that does not depend on the software used to implement it.

Answer 38

Software Independence

Question 39

A condition in which a model does not depend on the hardware used in the model’s implementation

Answer 39

Hardware Independence

Question 40

A stage in the design phase that matches the conceptual design to the requirements of the selected DBMS and is therefore software dependent.

Answer 40

Logical Design

Question 41

In database modeling, a level of ___ that adapts the conceptual model to a specific DBMS model for implementation.

Answer 41

Data Abstraction

Question 42

The ___ is the representation of a database as “seen” by the DBMS.

Answer 42

Internal Model

Question 43

In other words, the ___ requires a designer to match the conceptual model’s characteristics and constraints to those of the selected implementation model.

Answer 43

Internal Model

Question 44

A representation of an internal model using the database constructs supported by the chosen database.

Answer 44

Internal schema

Question 45

A condition in which the internal model can be changed without affecting the conceptual model.

Answer 45

Logical Independence

Question 46

A model in which physical characteristics such as location, path, and format are described for the data.

Answer 46

Physical Model

Question 47

The physical model is both ___

Answer 47

hardware and software-dependent.

Question 48

A condition in which the physical model can be changed without affecting the internal model.

Answer 48

Physical Independence

Question 49

Models and their Degrees of Abstraction

Answer 49

- External - Heighest - Conceptual - High - Internal - Low - Physical - Lowest

Question 50

Model and their Focus

Answer 50

- External - End-User Views - Conceptual - Global view of Data (Database model independence) - Internal - Specific Database model - Physical - Storage and Access methods

Question 51

Models and their Independence

Answer 51

- External - Hardware and Software - Conceptual - Hardware and Software - Internal - Hardware - Physical - Neither hardware nor software