Data Management

Question 1

What is a data model?

Answer 1

a simple representation that demonstrates data structures and their characteristics, relations, constraints, transformations, and other constructs to show how a database will solve a real-world business problem.

Question 2

business rule

Answer 2

a policy, procedure, or principle within a specific organization. business rules are used to define entities, attributes, relationships, and constraints.

Question 3

the basic features of the relational data model

Answer 3

entities, attributes, relationships

Question 4

Translate business rules into data models

Answer 4

a noun in a business rule will translate into an entity in the model, and a verb (active or passive) that associates the nouns will translate into a relationship among the entities

Question 5

entity

Answer 5

An entity is a person, place, thing, concept, or event about which data will be collected and stored.

Question 6

Attribute

Answer 6

An attribute is a characteristic of an entity. For example, a CUSTOMER entity would be described by attributes such as customer last name, customer first name, customer phone number, customer address, and customer credit limit.

Question 7

Relationships

Answer 7

A relationship describes an association among entities. Data models use three types of relationships: one-to-many, many-to-many, and one-to-one. Database designers usually use the shorthand notations 1:M or 1..*, M:N or .., and 1:1 or 1..1, respectively.

Question 8

Visualize One-to-many (1:M or 1..*) relationship.

Answer 8

An author has many books, but a book has one author 1:M AUTHOR publishes BOOKS
An invoice is created by one person, but a customer generates many invoices 1:M CUSTOMER generates INVOICES

Question 9

Visualize Many-to-many (M:N or ..) relationship.

Answer 9

An employee may learn many job skills, and each job skill may be learned by many employees. “EMPLOYEE learns SKILL” as M:N.
A student can take many classes and each class can be taken by many students, M:N STUDENT takes CLASSES

Question 10

One-to-one (1:1 or 1..1) relationship.

Answer 10

A retail company’s management structure may require that each of its stores be managed by a single employee. “EMPLOYEE manages STORE” is labeled 1:1.

Question 11

Schema

Answer 11

The schema is the conceptual organization of the entire database as viewed by the database administrator.

Question 12

Hierarchial model

Answer 12

Within the hierarchy, a higher layer is perceived as the parent of the segment directly beneath it, which is called the child. The hierarchical model depicts a set of one-to-many (1:M) relationships between a parent and its children segments.

Question 13

Network model

Answer 13

the user perceives the network database as a collection of records in 1:M relationships. However, unlike the hierarchical model, the network model allows a record to have more than one parent.

Question 14

Subschema

Answer 14

The subschema defines the portion of the database “seen” by the application programs that actually produce the desired information from the data within the database.

Question 15

Relational model

Answer 15

A relation (sometimes called a table) as a two-dimensional structure composed of intersecting rows and columns. Each row in a relation is called a tuple. Each column represents an attribute. The relational model also describes a precise set of data manipulation constructs based on advanced mathematical concepts.

Question 16

The Entity relationship model

Answer 16

The graphical representation of entities and their relationships in a database structure quickly became popular because it complemented the relational data model concepts. The relational data model and ERM combined to provide the foundation for tightly structured database design. ER models are normally represented in an entity relationship diagram (ERD),

Question 17

Object-Oriented Model (OODM)

Answer 17

the object-oriented data model (OODM), both data and its relationships are contained in a single structure known as an object. In turn, the OODM is the basis for the object-oriented database management system (OODBMS).

Question 18

Why is an object said to have greater semantic content than an entity?

Answer 18

an object includes information about relationships between the facts within the object, as well as information about its relationships with other objects. Therefore, the facts within the object are given greater meaning. The OODM is said to be a semantic data model because semantic indicates meaning.

Question 19

Class vs object

Answer 19

A class is a collection of similar objects with shared structure (attributes) and behavior (methods). An object is an abstraction of an entity

Question 20

Extensible Markup Language (XML)

Answer 20

emerged as the de facto standard for the efficient and effective exchange of structured, semistructured, and unstructured data. Organizations that used XML data soon realized that they needed to manage large amounts of unstructured data such as word-processing documents, webpages, emails, and diagrams.

Question 21

table

Answer 21

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.

Question 22

The 3 Vs

Answer 22

VOLUME: amounts of data being stored
VELOCITY: the speed which data grows but also the need to process
VARIETY: the fact that data is collected in multiple formats

Question 23

Internet of Things (IoT)

Answer 23

A web of Internet-connected devices constantly exchanging and collecting data over the Internet. IoT devices can be remotely managed and configured to collect data and interact with other devices on the Internet.

Question 24

What is Hadoop, and what are its basic components?

Answer 24

A Java-based, open-source file storage system that uses the write-once, read many model. This means that once the data is written, it cannot be modified.

Question 25

data

Answer 25

Raw facts, or facts that have not yet been processed to reveal their meaning to the end user.

Question 26

field

Answer 26

A character or group of characters (alphabetic or numeric) that has a specific meaning. A field is used to define and store data.

Question 27

record

Answer 27

A logically connected set of one or more fields that describes a person, place, or thing.

Question 28

file

Answer 28

A collection of related records. For example, a file might contain data about the students currently enrolled at Gigantic University.

Question 29

what is data redundancy?

Answer 29

Exists when the same data is stored unnecessarily at different places, leading to poor data security, inconsistency, entry errors, and integretiy problems

Question 30

The difference between data, info, and a database

Answer 30

the database system consists of logically related data stored in a single logical data repository. the current generation of DBMS software stores not only the data structures but also the relationships between those structures and the access paths to those structures

Question 31

What are the main components of a database?

Answer 31

Hardware, software, people, procedures or rules governing the design, and the data

Question 32

What is metadata?

Answer 32

The metadata describes the data characteristics and the set of relationships that links the data found within the database.

Question 33

Structured data vs. non-structured

Answer 33

Data that has been formatted to facilitate storage, use, and information generation in a predefined data model.

Question 34

Information

Answer 34

the result of processing raw data to reveal its meaning. Data processing can be as simple as organizing data to reveal patterns or as complex as making forecasts or drawing inferences using statistical modeling.

Question 35

data dictionary

Answer 35

A DBMS component that stores metadata—data about data. Thus, the data dictionary contains the data definition as well as their characteristics and relationships. A data dictionary may also include data that are external to the DBMS. Also known as an information resource dictionary. See also active data dictionary, metadata, and passive data dictionary.