Week 1

Question 1

Relational database system

Answer 1

Structured, (Operational workload,(backing, online store)

Question 2

So what we want here is to build systems, data processing systems,
data management systems that can cope with the

Answer 2

volume,

velocity and variety aspects of the big data

Question 3

NoSQL Graph doc, key-value stores

Answer 3

Unstructured data (highly available systems

Question 4

Hadoop, Spark

Answer 4

For analytics over massive scale data

Question 5

What kind of software should be used if one needs to store data online, make certain parts of it accessible by different user types, and searchable?

Answer 5

Database Management Software

Question 6

What is a characteristic of big data?

Answer 6

Data comes from different sources in Different formats

Question 7

What is a database

Answer 7

A very large integrated collection of data

Question 8

What does a database do?

Answer 8

Models relationships between these entities

Question 9

Three parts of a database management system (DBMS)

Answer 9

1) Store data
2) Retrieve Data
3) Manage Data

Question 10

6 Benefits of DBMS

Answer 10

1) Data Independence
2) Efficient Data Access
3) Data Integrity and Security
4) Data Administration
5) Concurrent Access and Recovery
6) Reduced App Development Time

Question 11

data independence

Answer 11

Isolate the user of the system from how the data is managed ad organized.

The person who’s building the application doesn’t need to know anything
about how the data is stored, how the data is organized inside the database.
All they care about is, again, the application and the database system
takes care of everything related to the organization of the data,
everything related to the performance, the scalability issues.

Question 12

efficient data access

Answer 12

So efficient data access means that if the application developer doesn’t have a database management system. Then you need to take care of how to, for example, index the data or how to efficiently retrieve the data from where it’s stored. And this is again a lot of burden on the user. So the database management system releases or
carries that burden and the user doesn’t need to do it

Question 13

Data Administration

Answer 13

And data administration means that you have just one location that you store the data in. And you have one portal to allow for an administrator

Question 14

Concurrent Access and Recovery

Answer 14

f you have multiple users using the data at the same time, you need to allow for concurrent access.
So concurrent access, the database management systems allow users to concurrently access and run transactions against the database

Question 15

Data Integrity and Security

Answer 15

So a database management systems takes care of how to secure the data stored in the database.
So we have heard recently of several data breaches like the Equifax data breach, or that happens sometimes. And if you have a really good database management system,
it takes care of the data security itself.

Question 16

Reduced App Development Time

Answer 16

So if you have a system that allows you to, to give you the efficient data access, it has one place for secure and integrated data, and also data independence.
The application developer all, what he or
she needs to focus on is just the logic of their own application instead of focusing on the scalability, efficiency, security of the database. So you just focus on the logic of the application.

Question 17

What does data independence mean for a DBMS?

Answer 17

Not required to know how the data in the application is stored

Question 18

What is a data model

Answer 18

A data model is a collection of concepts that describe the data.

Question 19

What is a schema

Answer 19

Is a description of the data a model

Question 20

What is an example of a data model

Answer 20

So the most widely used data model in database systems is the relational model

Question 21

relations =

Answer 21

table

Question 22

Each column represents

Answer 22

And each column represent an attribute of this entity

Question 23

W​hat is the relationship for the number of physical schemas to logical schemas in a DBMS?

1) n:1
2) 1:1
3) 1:n

Answer 23

2) 1:1

Question 24

Three types of schema

Answer 24

1) physical schema - The way the data is stored and organized
2) conceptual schema - how the data is logically represented (like relational model )
3) external schema / views - multiple external schemas in a database (collect info from different tables)

Question 25

What is logical data independence?

Answer 25

protects the user or
the application on top of the database from changes in the logical schema or
the logical structure of the data.

Question 26

What is physical data independence,

Answer 26

Protects the application

from changes in the physical schema or the physical structure of the data

Question 27

What is the most widely used data model today?

Answer 27

Relational Model

Question 28

Which of the following is true about data schemas?

Answer 28

There may be multiple external schemas for a given database

Question 29

Database design - Phase 1

Answer 29

Requirement Analysis

Question 30

Database design - Phase 2

Answer 30

Conceptual Database Design (draw the database_

Question 31

Database design - type of diagram

Answer 31

(ER) entity relationship model

Question 32

Database design - Phase 3

Answer 32

Logical Database Design

Question 33

In the example, what are the two entities in the company database?

1) Dept, Employee
2) Dept, Budget
3) Employeem, SSN

Answer 33

1) Dept, Employee

Question 34

In the example, what are the two entities in the company database?

1) Dept, Employee
2) Dept, Budget
3) Employeem, SSN

Answer 34

1) Dept, Employee

Question 35

3 types of relationships

Answer 35

1) 1 to 1
2) 1 to Many
3) Many to Many

Question 36

Weak Entities (ER)

Answer 36

Weak Entities can be identified uniquely only by considering the primary key of another entity (owner)

Question 37

Weak Entities (ER)

Answer 37

Weak Entities can be identified uniquely only by considering the primary key of another entity (owner)

Question 38

Example of Weak Entities (ER)

Answer 38

Family of dependents depends in a work database

Question 39

Rules of Weak Entities (ER)

Answer 39

1) must participate in a one-to-many relationship with a stronger entity.
2) a weak entity must have total participation in the relationship with the stronger entity

Question 40

In the example, can dependents be a primary key?

Answer 40

No, because it is a weak entity and must participate in relationship with employees.