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zhenek [66]
3 years ago
10

Suppose we have a relation schema R(A, B, C) with FD A rightarrow B. Suppose also that we decide to decompose this schema into S

(A, B) and T(B, C). Give an example of an instance of relation R whose projection onto S and T and subsequent rejoining as in Section 3.4.1 does not yield the same relation instance. That is, pi_A, B(R) pi_B, C (R) notequalto R.

Computers and Technology
1 answer:
4vir4ik [10]3 years ago
7 0

Answer:

Check the explanation

Explanation:

A relation schema is the fundamental schema for a table. Which is In a relational kind of database (what individuals naturally refer to when they talk about database) each take can be referred to as a "relation" . therefore a relational schema is the design for the table.

kindly check the attached image below to see the step by step solution to the question.

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Write a program that reads raw data from a file that contains an inventory of items. The items should be sorted by name, and the
Anika [276]

Answer:

//C++ code

#include<iostream>

#include<fstream>

#include<iomanip>

using namespace std;

/*===============================================*/

// a structure called prod

struct prod

{

string name;// – a string, assumed to have no spaces

double price; // –adollaramount

int inStock; // – the number of items currently in stock.

};

//Fucntion Prototypes

void readInventory(prod products[], int& size);

/*===============================================*/

/*returns: a dollar amount, the total value of the inventory*/

double totalValue(prod products[], int size);

/*===============================================*/

// Sorts the given array by name

void sort(prod products[], int size);

/*===============================================*/

/*a report to a file called “report.txt”.

When the file fails to open, print

“Unable to open output file.” and end.*/

void writeReport(prod products[], int size);

/*===============================================*/

//Function definitions

/*===============================================*/

void writeReport(prod products[], int size)

{

ofstream outfile("report.txt");

outfile << fixed << setprecision(2);

if (!outfile)

{

cout << "Unable to open output file.\n";

return;

}

outfile << "+------------------------------+\n | Current Inventory |\n\

\n+------------------------------+\nNAME PRICE #\n\

\n-------------------- ------- ---\n";

for (int i = 0; i < size; i++)

{

outfile << products[i].name << " " << products[i].price << " " << products[i].inStock << endl;

}

outfile << "+------------------------------+\n";

outfile << "Number of products: " << size << endl;

outfile << "Inventory total value: " << totalValue(products, size) << endl;

cout << "Report written to file\n";

//close the output stream

outfile.close();

}

/*===============================================*/

void sort(prod products[], int size)

{

for (int i = 0; i < size; i++)

{

for (int j = i+1; j < size; j++)

{

if (products[i].name > products[j].name)

{

//swapping

prod temp = products[i];

products[i] = products[j];

products[j] = temp;

}

}

}

}

/*===============================================*/

double totalValue(prod products[], int size)

{

double total = 0;

for (int i = 0; i < size; i++)

{

total += products[i].inStock * products[i].price;

}

return total;

}

/*===============================================*/

void readInventory(prod products[], int& size)

{

// Open a file called “inventory.txt”

//and read the data from the file into the partial array

//.If the file fails to open,

//print “Unable to open input file”

//and set the number of products to 0.

size = 0;

ifstream inFile("inventory.txt");

if (!inFile)

{

cout << "Unable to open input file.\n";

return;

}

string name;

double price;

int qunatity;

while (inFile >> price >>qunatity >>name)

{

if (price != -1 && qunatity != -1 && name != "endofdata")

{

products[size].name = name;

products[size].inStock = qunatity;

products[size].price = price;

size++;

}

}

cout << "inventory read\n";

//close the stream

inFile.close();

}

/*===============================================*/

int main()

{

//declares a partial array of products

prod products[100];

int size;

// invokes readInventory()

readInventory(products, size);

// invokes sort()

sort(products, size);

// invokes writeReport()

writeReport(products, size);

// ends with the standard system pause.

system("pause");

return 0;

}

please see attachment for inventory text and output.

4 0
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kotegsom [21]

Answer:

The correct answer to the following question will be "Valid-code test".

Explanation:

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  • To diagnose the given mistake, a valid code review will be the strongest internal control audit to incorporate into the organization's computer program.
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_______ are special incentives or excitement-building programs that encourage consumers to purchase a particular product, often
Damm [24]

Answer: sales promotion

Explanation:

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5 0
3 years ago
1
g100num [7]
Have a look at the man page for printf:

man 3 printf
4 0
3 years ago
Read 2 more answers
Define the computer with its workintg principple
GenaCL600 [577]

Explanation:

Computer is an electronic device that is designed to work with information.

WORKING PRINCIPLE OF COMPUTER

a.It accepts data and instructions by way of input,

b.It stores data,

c.It can process data as required by the user,

d.It gives result in the form of output,

e.It controls all operations inside a computer.

I hope it will help you

5 0
2 years ago
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