week 4

Question 1

_____________
The process of creating a specific data model for a determined problem domain.

___________
A representation, usually graphic, of a complex “real-world” data structure.
Data models are used in the database design phase of the Database Life Cycle.

Answer 1

data modeling
data model

Question 2

The Importance of Data Models

● ___________
Data models help bridge communication between designers, application programmers, and end users.
● ______________
A well-structured data model can provide a clearer understanding of how different parts of an organization fit
together.
● _______________
Different users (e.g., managers, clerks, programmers) view data from varying perspectives, and a data model
accommodates these diverse views.
● _____________
Like a blueprint for a house, a data model gives an overall, cohesive view of the data, ensuring consistency
across the organization.
● ____________
A well-designed data model avoids inconsistencies in data usage, which can otherwise lead to costly
mistakes.
● __________________
Just as a blueprint is essential to building a house, a data model is crucial for creating an efficient and
accurate database

Answer 2

Facilitates communication
Improves organizational understanding
Provides different perspectives
Offers a holistic view
Prevents conflicts
Guides database development

Question 3

Data Model Basic Building Blocks

● An _________ is a person, place, thing, or event about which data will be collected and stored. It
represents a particular type of object in the real world, which means an entity is “distinguishable” —
that is, each entity occurrence is unique and distinct.

● An ___________ is a characteristic of an entity
● A _____________ describes an association among entities
● A __________ is a restriction placed on the data. It is important because they help to
ensure data integrity. They are normally expressed in the form of rules:
○ An employees salary must have values that are between 6,000 and 350,000.
○ A student’s GPA must be between 0.00 and 4.00.
○ Each class must have one and only one teacher

Answer 3

entity
attribute
relationship
constraint

Question 4

Data Models use Three Types of Relationships

● ________________
Associations among two or more entities that are used by data models. One entity instance is associated with many instances of the related entity.

● ____________________
Association among two or more entities in which one occurrence of an entity is associated
with many occurrences of a related entity and one occurrence of the related entity is associated with
many occurrences of the first entity.

● __________________
Associations among two or more entities that are used by data models. In a 1:1 relationship,
one entity instance is associated with only one instance of the related entity

Answer 4

One-to-many (1:M or 1..*) relationship
Many-to-many (M:N or ..) relationship
One-to-one (1:1 or 1..1) relationship

Question 5

The Evolution of Data Models

Answer 5

➔ Hierarchical
➔ Network
➔ Relational
➔ Entity relationship
➔ Object oriented (00)

Question 6

_______________
An early database model whose basic concepts and characteristics formed the basis for subsequent
database development.
This model is based on an upside-down tree structure in which each record is called a ___________
The top record is the ____________. Each segment has a 1:M relationship to the segment directly below it.
The hierarchical model depicts a set of one-to-many (1:M) relationships between a parent and its children
segments.
➔ each parent can have many children
➔ each child has only one parent

Answer 6

Hierarchical model
segment.
root segment

Question 7

Benefits of Hierarchical Model

Efficiency: Allowed ____________ compared to file-based systems.
Clear Relationships: _____________ made it easy to see connections.
Example: Used in banking and telecommunication systems.

Limitations of Hierarchical Model

___________: Data relationships are inflexible; one-to-one or one-to-many relationships only.
_____________: Complex many-to-many relationships not easily represented.
________________: Difficult to search across branches

Answer 7

faster data retrieval
Simple parent-child structure

Rigidity
Difficult to Model Complex Data
Limited Query Flexibility

Question 8

________ was created to represent complex data relationships more effectively than the
hierarchical model, to improve database performance, and to impose a database standard.
● the user perceives the network database as a collection of records in 1:M
relationships.
● Network model allows a record to have more than one parent
Example: CODASYL DBTG (Conference on Data Systems Languages Database Task Group

Answer 8

Network Model

Question 9

Benefits of Network Model

_________: Supports complex data relationships that the hierarchical model couldn’t handle.
_____________: Users could efficiently navigate the graph structure to retrieve related records.
__________: Ideal for managing supply chains, telecommunications, and airline reservation systems.

Limitations of Network Model

____________: More complex to design and implement compared to hierarchical models.
_____________: Required expert knowledge to manage and query data.
___________: Changes to the database structure could be cumbersome.

Answer 9

Flexibility
Efficient Data Navigation
Use Cases
Complexity
Steep Learning Curve
Difficult to Modify

Question 10

Standard database concepts

○ The ___________ is the conceptual organization of the entire database as viewed by the database
administrator.
○ The_____________ defines the portion of the database “seen” by the application programs that actually
produce the desired information from the data within the database.
○ A _______________ (DML) defines the environment in which data can be managed and is
used to work with the data in the database.
○ A ________________ (DDL) enables the database administrator to define the schema
components

Answer 10

schema
subschema
data manipulation language
schema data definition language

Question 11

➢ developed by Codd of IBM in 1970
➢ is based on mathematical set theory and represents data as independent relations
➢ data stored in tables (relations), with rows (tuples) and columns (attributes)
➢ produced an “automatic transmission” database to replace the “standard transmission” databases
that preceded it
➢ is implemented through a very sophisticated relational database management system (RDBMS)
Key Features:
● Based on mathematical set theory
● Relations allow easy data manipulation and queries
Examples: SQL, Oracle, MySQL__

Answer 11

Relational Model

Question 12

Benefits of Relational Model

____________: Easier to understand and use compared to hierarchical and network models.
___________: SQL enables complex queries with simple commands.
___________: Tables can easily be joined to form new relationships.
______________: Relational databases like Oracle and MySQL are industry standards.

Limitations of Relational Model

______________: As data grows, relational databases can struggle with performance
and scalability.
_____________: Works best for structured data; less effective for unstructured data like multimedia.
_____________: Modifying the schema can be time-consuming, especially in large databases

Answer 12

Simplicity
Powerful Querying
Flexibility
Widespread Use

Performance Issues with Big Data
Structured Data Only
Schema Changes

Question 13

________________
❖ performs the same basic functions provided by the hierarchical and network DBMS systems, in
addition to a host of other functions that make the relational data model easier to understand and
implement

❖ most important advantage is its ability to hide the complexities of the relational
model from the user
❖ manages all of the physical details, while the user sees the relational database as a
collection of tables in which data is stored
❖ The software translates a user’s logical requests (queries) into commands that physically locate
and retrieve the requested data

Answer 13

Relational Database Management System (RDBMS)

Question 14

______________
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

____________
In the relational model, a table row

_____________
A graphical representation of a relational database’s entities, the attributes within those entities, and the
relationships among the entities

Answer 14

table (relation)
tuple
relational diagram

Question 15

A relational table stores a collection of related entities.

● Unlike a file, a relational table provides _________________.
● The table is a ____________; the physical storage of data is ________ to
users or designers.
● This __________ led to a significant breakthrough in database technology.
● The rise of the relational data model is due to its powerful and flexible____________
● SQL allows users to define what data to retrieve without specifying how to
retrieve it.
● SQL simplifies data retrieval compared to other database or file systems

Answer 15

complete data and structural
independence

logical structure
irrelevant
abstraction
query language, SQL.

Question 16

From an end-user perspective, an SQL-based relational database has three parts:
the __________________

_________________
Allows users to interact with data by automatically generating SQL code. Interfaces vary based on
the software vendor but can be customized with application generators.

A ______________ in the database
All data is stored in independent tables that present information in an easy-to-understand format.
Rows in different tables are linked by common attributes.

________
Executes data queries behind the scenes. It processes user requests for creating tables, accessing
data, and performing maintenance without users needing to know how it works, as SQL specifies what
must be done, not how

Answer 16

user interface, tables, and the SQL engine.

End-user interface
collection of tables stored

SQL engine

Question 17

________________
○ Widely accepted and adapted graphical tool for data modeling
○ Introduced by Chen in 1976
○ Graphical representation of entities and their relationships in a database structure
○ 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 17

Entity Relationship (ER) Model (ERM)

Question 18

The Entity-Relationship (ER) model is based on three main components:
___________ is any object or concept about which data is collected and stored.
In an Entity-Relationship Diagram (ERD), it is represented by a _________ with the entity’s name in capital
letters and singular form.

_____________: Each entity has it that describe particular characteristics. Attributes are detailed in
ERDs to provide information about each entity.

___________ describe associations among datar. They typically describe associations
between two entities and are categorized into one-to-many (1:M), many-to-many (M:N), and one-to-one
(1:1) types.

Answer 18

Entity
rectangle
Attributes
Relationships

Question 19

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

_______________
A row in a relational table.

___________
A collection of like entities.

________________
The type of relationship between entities.Classifications include 1:1, 1:M, and M:N.

_____________
A method for creating Entity-Relationship Diagrams (ERDs) where entities are represented by rectangles, attributes
by ovals, and relationships by diamonds, with cardinality shown through lines and annotations.

______________
A representation of the entity relationship diagram that uses a three-pronged symbol to represent the “many” sides of
the relationship.

___________
The set of symbols used in the creation of class diagrams

Answer 19

entity relationship diagram (ERD)
entity instance (entity occurrence)
entity set
Connectivity
Chen notation
Crow’s Foot notation
class diagram notation

Question 20

______________
Increasing complexity in real-world problems required a data model that better represents real-world
entities.

_____________
❏ Encapsulates both data and relationships in a single structure known as an __________.
❏ Basis for Object-Oriented Database Management System (OODBMS).
❏ Is said to be a _______________

Answer 20

Object Oriented Model
Object-Oriented Data Model (OODM):
object
semantic data model

Question 21

OODM Components

________ Abstractions of real-world entities, representing individual occurrences of an entity.
__________ Properties that describe an object’s characteristics, such as Name or Social Security Number for a PERSON
object.
_________ Collections of similar objects with shared attributes and methods, defining the structure and behavior of objects.
Classes group objects and include methods that define their actions.

__________ An organizational structure resembling an upside-down tree, where each class has a single parent class,
allowing for inheritance of attributes and methods.

__________ The ability for subclasses to inherit attributes and methods from parent classes, facilitating reuse and
extension of existing class definitions.

____________ Used to visually represent the structure and relationships of objects within the system, based on
object-oriented concepts.

Answer 21

Objects:
Attributes:
Classes:
Class Hierarchy:
Inheritance:
UML Class Diagrams:

Question 22

______________
Data management software used to manage data in an object-oriented database model.

______________
The first of a series of data models that models both data and their relationships in a single
structure known as an object.

__________
A collection of similar objects with shared structure (attributes) and behavior (methods). A class
encapsulates an object’s data representation and a methods implementation.

___________
In the object-oriented data model, a named set of instructions to perform an action. Represents real-world actions

Answer 22

object-oriented database management system (OODBMS)

semantic data model
class
method

Question 23

Object/Relational and XML

_____________________________
A model that includes the object-oriented model’s best features in an inherently simpler relational database
structural environment.

_____________________
A DBMS based on the extended relational model (ERDM). The ERDM, championed by many relational
database researchers, constitutes the relational model’s response to the OODM. This model includes many of the
object-oriented model’s best features within an inherently simpler relational database structure.

_________________
A metalanguage used to represent and manipulate data elements. Unlike other markup languages,
XML permits the manipulation of a document’s data elements. XML facilitates the exchange of
structured documents such as orders and invoices over the Internet

Answer 23

extended relational data model (ERDM)

object/relational database management system (O/R DBMS)

Extensible Markup Language (XML)

Question 24

Emerging Data Models: Big Data and NoSQL

_________ refers to a movement to find new and better ways to manage large amounts of web- and
sensor-generated data and derive business insight from it, while simultaneously providing high
performance and scalability at a reasonable cost.
Basic characteristics of Big Data databases*: ______________

Answer 24

Big Data
volume, velocity, and variety, or the 3 Vs

Question 25

Basic characteristics of Big Data databases: 3 Vs

________ refers to the amounts of data being stored.
Furthermore, organizations are using multiple technologies to interact with end users and those technologies are
generating mountains of data. This ever-growing volume of data quickly reached petabytes in size, and it’s still growing
.
__________ refers not only to the speed with which data grows but also to the need to process this data
quickly in order to generate information and insight.

its data growth is also due to the increase in the number of different data streams from which data is
being piped to the organization (via the web, e-commerce, Tweets, Facebook posts, emails, sensors, GPS, and so on).

___________ refers to the fact that the data being collected comes in multiple different data formats.
A great portion of these data comes in formats not suitable to be handled by the typical operational databases based
on the relational model.

Answer 25

Volume
Velocity
Variety

Question 26

Some of the most frequently used Big Data technologies are Hadoop,
MapReduce, and NoSQL databases.

___________
➔ is a Java-based, open-source, high-speed, fault-tolerant distributed storage and computational framework.
➔ uses low-cost hardware to create clusters of thousands of computer nodes to store and process data. Hadoop
originated from Google’s work on distributed file systems and parallel processing and is currently supported by the
Apache Software Foundation.
➔ has several modules, but the two main components are Hadoop Distributed File System (HDFS) and MapReduce.

________________
➔ is a highly distributed, fault-tolerant file storage system designed to manage large amounts of data at high speeds.
➔ In order to achieve high throughput, HDFS uses the write-once, read many model. This means that once the data is
written, it cannot be modified.
➔ HDFS uses three types of nodes: a name node that stores all the metadata about the file system, a data node
that stores fixed-size data blocks (that could be replicated to other data nodes), and a client node that acts as the
interface between the user application and the HDFS.

Answer 26

Hadoop
Hadoop Distributed File System (HDFS)

Question 27

______________
➔ is an open-source application programming interface (API) that provides fast data analytics services.
➔ distributes the processing of the data among thousands of nodes in parallel.
➔ works with structured and nonstructured data.
➔ The MapReduce framework provides two main functions:Map and Reduce.
➔ Map function takes a job and divides it into smaller units of work, and the Reduce function collects all the output
results generated from the nodes and integrates them into a single result set.

___________
➔ is a large-scale distributed database system that stores structured and unstructured data in efficient ways

Answer 27

MapReduce
NoSQL

Question 28

_____________________
The American National Standards Institute (ANSI) Standards Planning and Requirements Committee
(SPARC) defined a framework for data modeling based on degrees of data abstraction.

The resulting ANSI/SPARC architecture defines three levels of data abstraction: ________________

_____________
The group that accepted the DBTG recommendations and augmented database standards in 1975
through its SPARC committee

Answer 28

Degrees of Data Abstraction

external, conceptual, and
internal.
American National Standards Institute (ANSI)

Question 29

_______________
is the end users’ view of the data environment.
The term end users refers to people who use the application programs to manipulate the data and
generate information. End users usually operate in an environment in which an application has a specific
business unit focus.

Because data is being modeled, ER diagrams will be used to represent the external views. A specific
representation of an ______________ is known as an external schema

Answer 29

The External Model
external view

Question 30

The use of external views that represent subsets of the database has some important
advantages:

● It is ________ specific data required to support each business unit’s operations.
● It makes the designer’s job easy by providing _________ about the mode’s adequacy.
● It helps to ensure __________ in the database design.
○ Damaging an entire database is more _______ when each business unit works with only a
subset of data.
● It makes application program development much ________

Answer 30

easy to identify
feedback
security constraints
difficult
simpler

Question 31

➔ represents a global view of the entire database by the entire organization.
➔ integrates all external views (entities, relationships, constraints, and processes) into a single global view of the data
in the enterprise.

➔ most widely used conceptual model is the __________

________________
● it is the basis for the identification and high-level description of the main data objects (avoiding any database
model-specific details)
● a representation of the conceptual model, usually expressed graphically

Answer 31

The Conceptual Model
ER model.

Conceptual schema

Question 32

The conceptual model yields some important advantages.
1 It provides a ________ view of the data environment that is relatively easy to understand.
2 It is independent of both software and hardware.

____________ means that the model does not depend on the DBMS software used to
implement the model.
________________ means that the model does not depend on the hardware used in the
implementation of the model.

Therefore, changes in either the hardware or the DBMS software will have no effect on the database design at the
conceptual level. Generally, the term ____________ refers to the task of creating a conceptual data model that
could be implemented in any DBMS

Answer 32

bird’s-eye (macro level)
Software independence
Hardware independence
logical design

Question 33

_______________
● once a specific DBMS has been selected, the internal model maps the conceptual model to the
DBMS.
● is the representation of the database as “seen” by the DBMS.
● requires the designer to match the conceptual model’s characteristics and constraints to those of
the selected implementation model.
● an internal schema depicts a specific representation of an internal model, using the database
constructs supported by the chosen database.
● because the internal model depends on specific database software, it is said to be software
dependent.

Answer 33

The Internal Model

Question 34

________________
● operates at the lowest level of abstraction, describing the way data is saved on storage media such
as magnetic, solid state, or optical media. T
● requires the definition of both the physical storage devices and the (physical) access methods
required to reach the data within those storage devices, making it both software and hardware
dependent.

Although the relational model does not require the designer to be concerned about the datas physical
storage characteristics, the implementation of a relational model may require physical-level fine-tuning for
increased performance.

____________ is especially important when very large databases are installed in a mainframe
environment, yet even such performance fine-tuning at the physical level does not require knowledge of
physical data storage characteristics__

Answer 34

The Physical Model
Fine-tuning