Cual es la importancia de aplicar los pasos en el modelo de diseño en las actividades académicas?

[1] Please find all the candidate keys and the primary key (or composite primary key) Candidate Key: _______________________ Pri

AVprozaik [17]

Answer:

Check the explanation

Explanation:

1. The atomic attributes can't be a primary key because the values in the respective attributes should be unique.

So, the size of the primary key should be more than one.

In order to find the candidate key, let the functional dependencies be obtained.

The functional dependencies are :

Emp_ID -> Name, DeptID, Marketing, Salary

Name -> Emp_ID

DeptID -> Emp_ID

Marketing -> Emp_ID

Course_ID -> Course Name

Course_Name -> Course_ID

Date_Completed -> Course_Name

Closure of attribute { Emp_ID, Date_Completed } is { Emp_ID, Date_Completed , Name, DeptID, Marketing, Salary, Course_Name, Course_ID}

Closure of attribute { Name , Date_Completed } is { Name, Date_Completed , Emp_ID , DeptID, Marketing, Salary, Course_Name, Course_ID}

Closure of attribute { DeptID, Date_Completed } is { DeptID, Date_Completed , Emp_ID,, Name, , Marketing, Salary, Course_Name, Course_ID}

Closure of attribute { Marketing, Date_Completed } is { Marketing, Date_Completed , Emp_ID,, Name, DeptID , Salary, Course_Name, Course_ID}.

So, the candidate keys are :

{ Emp_ID, Date_Completed }

{ Name , Date_Completed }

{ DeptID, Date_Completed }

{ Marketing, Date_Completed }

Only one candidate key can be a primary key.

So, the primary key chosen be { Emp_ID, Date_Completed }..

2.

The functional dependencies are :

Emp_ID -> Name, DeptID, Marketing, Salary

Name -> Emp_ID

DeptID -> Emp_ID

Marketing -> Emp_ID

Course_ID -> Course Name

Course_Name -> Course_ID

Date_Completed -> Course_Name

3.

For a relation to be in 2NF, there should be no partial dependencies in the set of functional dependencies.

The first F.D. is

Emp_ID -> Name, DeptID, Marketing, Salary

Here, Emp_ID -> Salary ( decomposition rule ). So, a prime key determining a non-prime key is a partial dependency.

So, a separate table should be made for Emp_ID -> Salary.

The tables are R1(Emp_ID, Name, DeptID, Marketing, Course_ID, Course_Name, Date_Completed)

and R2( Emp_ID , Salary)

The following dependencies violate partial dependency as a prime attribute -> prime attribute :

Name -> Emp_ID

DeptID -> Emp_ID

Marketing -> Emp_ID

The following dependencies violate partial dependency as a non-prime attribute -> non-prime attribute :

Course_ID -> Course Name

Course_Name -> Course_ID

So, no separate tables should be made.

The functional dependency Date_Completed -> Course_Name has a partial dependency as a prime attribute determines a non-prime attribute.

So, a separate table is made.

The final relational schemas that follows 2NF are :

R1(Emp_ID, Name, DeptID, Marketing, Course_ID, Course_Name, Date_Completed)

R2( Emp_ID , Salary)

R3 (Date_Completed, Course_Name, Course_ID)

For a relation to be in 3NF, the functional dependencies should not have any transitive dependencies.

The functional dependencies in R1(Emp_ID, Name, DeptID, Marketing, Date_Completed) is :

Emp_ID -> Name, DeptID, Marketing

This violates the transitive property. So, no table is created.

The functional dependencies in R2 ( Emp_ID , Salary) is :

Emp_ID -> Salary

The functional dependencies in R3 (Date_Completed, Course_Name, Course_ID) are :

Date_Completed -> Course_Name

Course_Name -> Course_ID

Here there is a transitive dependency as a non- prime attribute ( Course_Name ) is determining a non-attribute ( Course_ID ).

So, a separate table is made with the concerned attributes.

The relational schemas which support 3NF re :

R1(Emp_ID, Name, DeptID, Course_ID, Marketing, Date_Completed) with candidate key as Emp_ID.

R2 ( Emp_ID , Salary) with candidate key Emp_ID.

R3 (Date_Completed, Course_Name ) with candidate key Date_Completed.

R4 ( Course_Name, Course_ID ). with candidate keys Course_Name and Course_ID.

6 0

3 years ago

Which of the following statement is False? 1 point Context free language is the subset of context sensitive language Regular lan

alisha [4.7K]

Answer:

Context-sensitive language is a subset of context-free language

Explanation:

Considering the available options, the statement that is considered wrong is "Context-sensitive language is a subset of context-free language."

This is because generally every regular language can be produced through the means of context-free grammar, while context-free language can be produced through the means of context-sensitive grammar, and at the same time, context-sensitive grammars are produced through the means of Recursively innumerable.

Hence, the correct answer in this correct answer to the question is the last option *Context-sensitive language is a subset of context-free langage

3 0

3 years ago

owever, sitting in a corner of the store, a hacker had just set up an open "rogue" wireless hotspot posing as the coffee shop’s

Ivenika [448]

However, sitting in a corner of the store, a hacker had just placed up an open “rogue” wireless hotspot posing as the coffee shop’s wireless network. When Sarah logged onto her bank’s website, the hacker hijacked her session and gained access to her bank accounts. Another term for rogue wireless hotspots exists as “evil twin” hotspots.

<h3>What is meant by wireless network?</h3>

A computer network is referred to as a wireless network if radio frequency (RF) links are used to connect network nodes. A common solution for households, companies, and telecommunications networks is wireless networking. Wi-Fi is a wireless networking technology that enables printers and video cameras to connect to the Internet as well as computers (laptops and desktops), mobile devices (smart phones, wearables, etc.), and other devices.

Increased Mobility: Wireless networks give mobile users access to real-time data, enabling them to move freely across the premises of your firm without losing network connectivity. This improves collaboration and production across the entire organisation, which is not achievable with traditional networks.

Hence, However, sitting in a corner of the store, a hacker had just placed up an open “rogue” wireless hotspot posing as the coffee shop’s wireless network. When Sarah logged onto her bank’s website, the hacker hijacked her session and gained access to her bank accounts. Another term for rogue wireless hotspots exists as “evil twin” hotspots.

To learn more about wireless network refer to:

brainly.com/question/26956118

#SPJ4

6 0

1 year ago

Nila has created a report, and now she would like to a create table of contents. Nila has reviewed her report and decides to add

Alenkinab [10]

Answer:

The answer is "heading"

Explanation:

Headings, which appear into your document must be marked simply, objectively and correctly because it shows the final report structure and enable to easy access with specific information.

It also promotes to read the document. So, its consistency is ensured in the headings.
In sort documents, it can't require any heading, but it Nila created a report, in which she requires heading and then she update the content of the tables, and other choices can't be described in the given scenario, that's why it is correct

5 0

3 years ago

Describe at least one issue of terrorism that has happened recently.

zvonat [6]

Answer:

The republicans storming the capitol

Explanation:

6 0

3 years ago