What is htc one mseven

Assume you are using the MINUS operator to combine the results from two tables with identical structure, CUSTOMER and CUSTOMER_2

MariettaO [177]

The result of MINUS operator will be 10 - 2 = 8 records (number of records in CUSTOMER - number of common records).

5 0

3 years ago

[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

¿En qué países se ha implementado un sistema de vigilancia a través de drones?, ¿qué aspectos positivos y negativos ha generado?

mel-nik [20]

Answer:

17 países.

Explicación:

Hay diecisiete países que tienen vehículos aéreos no tripulados armados y donde se ha implementado un sistema de vigilancia con drones. Los drones son excelentes para recopilar grandes cantidades de datos de imágenes. Se puede implementar fácilmente para la vigilancia y mantener la seguridad. Se puede conducir a través de la computadora, no del piloto en él, por lo que el piloto se guarda. Los aspectos negativos de los drones es que tienen tiempos de vuelo cortos y el clima puede afectar fácilmente a los drones. Las operaciones precisas son difíciles y también eliminan futuros trabajos.

7 0

3 years ago

Create an application for a library and name it FineForOverdueBooks. TheMain() method asks the user to input the number of books

andrew11 [14]

Answer:

//The Scanner class is imported which allow the program to receive user input

import java.util.Scanner;

//Class Solution is defined to hold problem solution

public class Solution {

// The main method which signify the begining of program execution

public static void main(String args[]) {

// Scanner object 'scan' is defined to receive input from user keyboard

Scanner scan = new Scanner(System.in);

// A prompt is display asking the user to enter number of books

System.out.println("Please enter number of books: ");

// the user response is assigned to numberOfBook

int numberOfBook = scan.nextInt();

// A prompt is displayed asking the user to enter the number of days over due

System.out.println("Please enter number of days over due: ");

// the user response is assigned to numberOfDaysOverDue

int numberOfDaysOverDue = scan.nextInt();

//displayFine method is called with numberOfBook and numberOfDaysOverDue as arguments

displayFine(numberOfBook, numberOfDaysOverDue);

}

//displayFine method is declared having two parameters

public static void displayFine(int bookNumber, int daysOverDue){

// fine for first seven days is 10cent which is converted to $0.10

double firstSevenDay = 0.10;

// fine for more than seven days is 20cent which is converted to $0.20

double moreThanSevenDay = 0.20;

// the fine to be paid is declared

double fine = 0;

// fine is calculated in the following block

if(daysOverDue <= 7){

//the fine if the over due days is less than or equal 7

fine = bookNumber * daysOverDue * firstSevenDay;

} else{

// the extra days on top of the first seven days is calculated and assigned to extraDays

int extraDays = daysOverDue - 7;

//fine for first seven days is calculated

double fineFirstSevenDays = bookNumber * 7 * firstSevenDay;

// fine for the extradays is calculated

double fineMoreThanSevenDays = bookNumber * extraDays * moreThanSevenDay;

// the total fine is calculated by adding fine for first seven days and the extra days

fine = fineFirstSevenDays + fineMoreThanSevenDays;

}

// The total fine is displayed to the user in a nice format.

System.out.printf("The fine for " + bookNumber + " book(s) for " + daysOverDue + " day(s) is: $%.02f", fine);

}

Explanation:

The program first import Scanner class to allow the program receive user input. Then the class Solution was defined and the main method was declared. In the main method, user is asked for number of books and days over due which are assigned to numberOfBook and numberOfDaysOverDue. The two variable are passed as arguments to the displayFine method.

Next, the displayFine method was defined and the fine for the first seven days is calculated first if the due days is less than or equal seven. Else, the fine is calculated for the first seven days and then the extra days.

The fine is finally displayed to the user.

4 0

3 years ago

Password cracking is a technique used to extract user’s password of application/files without the knowledge of the legitimate us

Vlada [557]

Answer:

Rule based Attack.

Explanation:

As password cracking is a technique used to extract user’s password of application/files without the knowledge of the legitimate user. The attacker can use Rule Based Attack to find the password and to intrude or compromise the network and systems.

This is like a programming language to generate the password. This involves functions to modify, cut, edit and extend the generally used terms by the user.

5 0

3 years ago

What is htc one mseven​

What is htc one mseven