Consider the relational schema below: Students(sid: integer, sname: string, major: string) Courses(cid: integer, cname: string, hours: integer) Enrollment(sid: integer, cid: integer, grade: real) Write a relational algebra expression that satisfies this query? Find the distinct names of all students that take at least three courses and major in "Philosophy".

Answers

Answer 1

Solution :

Here, we need to perform JOIN operation of the students and registration.

Use NATURAL JOIN operator [tex]\Join[/tex] and so no need to specify Join condition.

Also we need to selection operator tp select only those course whose major in "philosophy".

Finally we projection operator π to project only distinct students name who took at least three courses.

[tex]$\pi [\sigma_{\text{student's nam}e} [ \sigma(\text{three courses}) \Join \text{"Philosophy"}]]$[/tex]


Related Questions

what is the difference between packed and unpacked bcd numbers ​

Answers

Explanation:

Packed BCD ( Binary coded decimal) is type in which each decimal digit is represented by 4 bits ( 1 nibble) . For Example : 14 will be shown as 0001 0100 in packed BCD form. Unpacked BCD is type in which each decimal digit is represented by 8 bits ( 1 byte).

In what tab can a user find the workspace option?

Answers

D. View.
You can find the workspace and preview of the file in View.

Which one is the result of the output given by a compute

Answers

Answer:

Images.

Sound.

Hardcopy

Answer:

it can be anything like sound or pictures

Explanation:

advantages of computational skill

Answers

Explanation:

algorithmic thinking - developing a set of instructions or sequence of steps to solve a problem;

evaluation - ensuring a solution is fit-for-purpose;

decomposition - breaking a problem down into its component parts;

What is system software? Write its types.​

Answers

Answer:

There are two main types of software: systems software and application software. Systems software includes the programs that are dedicated to managing the computer itself, such as the operating system, file management utilities, and disk operating system (or DOS)

Answer:

There are two main types of software: systems software and application software. Systems software includes the programs that are dedicated to managing the computer itself, such as the operating system, file management utilities, and disk operating system (or DOS)

Explanation:

thanks for question

why do we need vector graphics for creating logo​

Answers

Answer:

hope it will help u

please mark brillient

Answer:

So we can maintain high quality designs at any graphic scale.

Explanation:

Unlike other graphic formats which simply define colors for fixed pixels, vector graphics define points and shapes (vectors) which are then used to draw the graphic at the desired and appropriate resolution.

Our graphic can look good at any resolution, no matter how large it gets. If we take a png or jpg file and make it extremely large, you'll notice the image begins to get blurry, because the pixels are being stretched and colors are being predicted or matched for the larger scale.

What is the iterative procedure of recursive and nonrecursive?

Answers

Answer:

nonrecursive

Explanation:

cpp Write a program that first gets a list of integers from input. The input begins with an integer indicating the number of integers that follow. Then, get the last value from the input, which indicates a threshold. Output all integers less than or equal to that last threshold value. Ex: If the input is:

Answers

Answer:

#include <iostream>

int main() {

 // The length of the list

 int l;

 // The array containing the numbers

 int *list;

 // Threshold, last value in array

 int thresh;

 

 // Read in first value and create an array with the size of that value

 scanf("%d", &l);

 list = (int*) malloc(l * sizeof(int));

 

 for(int i = 0; i < l; i++) {

   scanf("%d", &list[i]);

 }

 thresh = list[l - 1];

 // Print the values

 for(int i = 0; i < l - 1; i++) {

   if (list[i] <= thresh) {

     printf("%d ", list[i]);

   }

 }

 

 printf("\n");

 free(list);

}

Explanation:

The program assumes at least two values are provided. The length of the list and the threshold.

We first read in an integer, and find out how many more integers we need to read. We create an array with the appropriate size, and loop through to fill the array with values. We know the last value is the threshold, and so we do one more loop to compare the values in the array with the threshold.

In regard to segmentation, all of the following are examples of a customer's behavior or relationship with a product EXCEPT: a) user status. b) loyalty status. c) usage rate. d) demographics

Answers

Answer: demographics

Explanation:

Market segmentation refers to the process of dividing the consumers into sub-groups of consumers which are refered to as the segments based on the characteristics shared.

The examples of a customer's behavior or relationship with a product include user status, usage rate and loyalty status.

It should be noted that some examples of market segmentation are behavioral, demographic, geographic, and psychographic. From the options given, demographics is not an example of a customer's behavior with a product.

How to use the AI System ?

Answers

ANSWER:

· New artificial intelligence systems are being developed to help teachers administer more effective testing that could uncover some of these often-hidden conditions. Once they can be properly identified, educators can tap into the resources available for a learning disability. Students can use AI to give reliable feedback.

Neymar machine that Run on electricity

Answers

"Neymar" = "name a"?

if so, well, there are many, like the little glowing box you use the type questions to the brainliest community, let it be a phone, a pc, or a molded Nintendo

if you meant Neymar indeed, I'm not sure if he runs on electricity, unless he is a soccer playing android somehow.

(1)similarities between backspace key and delete key. (2) different between backspace key and delete key. (3) explain the term ergonomics. (4) explain the following. a click b right click c double click d triple click e drag and drop​

Answers

Answer:

1.similarity:

they are both editing keys

3.ergonomics are designed keying devices that alleviates wrist strain experienced when using ordinary keyboard for long hours

4.

.a click is pressing and releasing the left mouse button onceright click is pressing the right mouse button once to display a short cut menu with commands from which a user can make a selectiondouble click is pressing the left button twice in rapid successiondrag and drop is where by the user drags an icon or item from one location on the screen to another.

Discuss the scaled index addressing mode and comments on the following instructions?

a) MOV BX, [CX+5*AX]
b) MOV [DX5*DI+30H], CX

Answers

Memory will also be accessible in Scaled index addressing mode using a 32-bit base & indexing register.The instruction's first parameter will be the base register, and the instruction's second parameter will be the index register. The index register is multiplied by a scaling factor before the program is fetched.

For option a:

The baseline register is [tex]\bold{BX}[/tex], while the index register is [tex]\bold{CX+5*AX}[/tex].

The multiplier for Accumulator [tex]\bold{AX }[/tex] will be 5.[tex]\bold{CX }[/tex] will be multiplied with this value.[tex]\bold{CX+5*AX}[/tex] will contain a memory address.The value at position [tex]\bold{CX+5*AX}[/tex] is accessed by [tex]\bold{[{CX+5*AX} ]}[/tex].The value retrieved from the address [tex][\bold{CX+5*AX}][/tex] is moved into Base register BX by the MOV instruction.

For option b:

Its index register is [tex]\bold{CX }[/tex], whereas the base register is [tex]\bold{DX5*DI+30H}[/tex].

[tex]\bold{CX}[/tex] has a number, that is copied to a computed place below.After multiplying [tex]\bold{DI}[/tex] by [tex]\bold{5, DX}[/tex] will be multiplied by this [tex]\bold{5*DI}[/tex].To the aforementioned multiplied value,[tex]\bold{ 30H}[/tex] will be added.[tex]\bold{[DX5*DI+30H]}[/tex] is a value located at location [tex]\bold{DX5*DI+30H}[/tex]. [tex]\bold{DX5*DI+30H }[/tex] is a memory address number.As a result, the value of [tex]\bold{CX}[/tex] will be copied to the [tex]\bold{ [DX5*DI+30H] }[/tex]location.

Learn more:

brainly.com/question/14319860

A choropleth map is used to
Group of answer choices

do a scatter plot.

show live satellite images.

present geographical regions in 3D.

present geographical regions coloured, shaded, or graded according to some variable.

Answers

4- present geographical regions colored, shaded, or graded according to some variable :)

Your location has been assigned the 172.149.254.0 /24 network. You are tasked with dividing the network into 13 subnets with the maximum number of hosts possible on each subnet.

Required:
a. What is the dotted decimal value for the subnet mask?
b. How many additional bits will you need to mask in the subnet mask?

Answers

The subnet mask would be a 32-bit integer which is formed by assigning the host bits to all 0's and the networking bits to so many 1's.In this method, the subnetting separates the IP address between host and network addresses.The subnet mask covers an IP address with its 32-bit number, thus the term "mask".

Given:

Network IP address [tex]\bold{= 172.149.254.0 /24}[/tex]

Subnet numbers [tex]\bold{= 13}[/tex]

Calculating the borrow bits:

[tex]\to \bold{= ceil(\log_{2} 13) = 4 \ bits}[/tex]

a)

Calculating the dotted decimal value for the subnet mask:

[tex]\to \bold{11111111.11111111.11111111.00000000}\\\\\to \bold{255.255.255.240}\\\\[/tex]

b)

The additional bits which will be needed to mask the subnet mask that is = 4.

Learn more: brainly.com/question/2254014

Create union integer with members char c, short s, int i and long b. Write a program that inputs the values of type char, short, int, and long and stores the values in union variables of type union integer. Each union variable should be printed as a char, a short, an int and a long. D the values always print correctly? Also create pseodocode or flowchart.
Here is the feedback that I received when I originally turned this in:
I have the following concerns: You need to save your program file with a .c extension. You should declare your union above the main module and then utilize it from within this portion. You have declared the union and then created a function definition prior to entering the main() function.
Here is the original code provided by homework help: Thanks in advance
#include
union myUnion {
char c;
short s;
int i;
long l;
};
void print(myUnion u) {
printf("As a character: %c\n", u.c);
printf("As a short: %hd\n", u.s);
printf("As an int: %d\n", u.i);
printf("As a long: %ld\n\n", u.i);
}
int main() {
myUnion u;
printf("Please enter a character: ");
scanf("%c", &(u.c));
print(u);
printf("Please enter a short: ");
scanf("%hd", &(u.s));
print(u);
printf("Please enter an int: ");
scanf("%d", &(u.i));
print(u);
printf("Please enter a long: ");
scanf("%ld", &(u.l));
print(u);
return 0;

Answers

Answer:

The updated program in C is as follows:

#include <stdio.h>

union myUnion{ char c; short s; int i; long l; };

int main(){

   union myUnion inputs;

   printf("Character: ");    scanf("%c", &inputs.c);

   printf("Output: %c", inputs.c);

   printf("\nShort: ");    scanf("%hd", &inputs.s);

   printf("Short: %hd", inputs.s);

   printf("\nInteger: ");    scanf("%d", &inputs.i);

   printf("Output: %d", inputs.i);

   printf("\nLong: ");    scanf("%ld", &inputs.l);

   printf("Long: %ld", inputs.l);

   return 0;

   }

The pseudocode is as follows:

Function union myUnion {

character; short; int; long

}

main() {

myUnion inputs;

Input inputs.c;  Print inputs.c

Input inputs.s; Print inputs.s

Input inputs.i; Print inputs.i;

Input inputs.l; Print inputs.l

}

Explanation:

This defines the union function

union myUnion{ char c; short s; int i; long l; };

The main begins here

int main(){

This calls the union function to main

   union myUnion inputs;

This prompts and gets input for character variable

   printf("Character: ");    scanf("%c", &inputs.c);

This prints the character input

   printf("Output: %c", inputs.c);

This prompts and gets input for short variable

   printf("\nShort: ");    scanf("%hd", &inputs.s);

This prints the short input

   printf("Short: %hd", inputs.s);

This prompts and gets input for integer variable

   printf("\nInteger: ");    scanf("%d", &inputs.i);

This prints the integer input

   printf("Output: %d", inputs.i);

This prompts and gets input for long variable

   printf("\nLong: ");    scanf("%ld", &inputs.l);

This prints the long input

   printf("Long: %ld", inputs.l);

   return 0;

   }

If you were driving the blue Prius in the situation pictured above, explain why the red Mustang should be given right-of-way at this intersection.

Answers

Answer:

The red Mustang should be given the right-of-way at this intersection because:

The red Mustang arrived first before the blue Prius and is closer to the stop sign before the arrival of the blue Prius.  This implies that the red Mustang must have waited for its turn, unlike the blue Prius that just arrived at the intersection.

Explanation:

Traffic laws, regulations, and IPDE defensive driving strategy require that drivers always give way to the vehicle that arrived before them at an intersection.   Assuming that multiple vehicles reach the intersection simultaneously, then the vehicle must be given the right-of-way.  Alternatively, the traffic lights at the intersection should be obeyed and be allowed to regulate the movement of vehicles.  IPDE defensive driving strategy requires drivers to be watchful of their driving spaces to determine the appropriate time to move.

When we have signals within 1-2 MHz band, using a waveguide is the most preferred choice for a transmission line. T or F?​

Answers

Answer:

T

Explanation:

you are the network administrator for a college. wireless access is widely used at the college. you want the most secure wireless connections you can have. which of the following would you use?
A WPA
B WEP2
CWEP
D WPA2

Answers

Answer:

D. WPA2

Explanation:

Required

Of the 4 options, which is the most secured?

WPA was created as a solution to the vulnerabilities in WEP/WEP2. Then, WPA was upgraded to WPA2.

WPA2 is the least vulnerable to hacks because for every user that is connected to the network through WPA2, a unique encryption is made available for such connection.

Hence, the most secure connection, of the 4 is WPA2.

They are correct? thank you!

Answers

Answer:

[OPINION]

First one is correct.

For the second one, I think the leader should accept the invitation and forward it to the entire team. [As the team experienced success due to group work, so every team member should be invited... as the success was a result of the hardwork of every member]

About the third one, I think it depends on the person so you may be correct. But, if I was asked to choose I would have been chosen.... rational approach

This is just my opinion. Hope it helps you:)

What is hacking? Why is hacking a concern for law enforcement?

Answers

Answer:

hacking is the act of exploitation, and is typically used to steal other people's account. It is a major concern because people can easily lose their account to hackers if they're too gullible, and the hacker can use their victims' accounts to purchase the things that they want with their victims' money.

Hacking is having unauthorized access to data in a computer or a system. It's a huge concern because everything nowadays depends on the internet, and every device connected to the Internet is at risk

The internet's data pathways rely on what kind of hardware device to route data to its destination?
servers

routers

IP addresses

ISPs

Answers

Answer:

Routers

Explanation:

Essentially a router is a device used in networking that route packets of data from one computer network to another.

Answer:

routers

Explanation:

Routers are hardware devices that route the data from place to place. Data "hops" from one router to another until it reaches its destination. ISPs and IP addresses are not hardware devices. Servers are hardware devices but do not route data.

-Edge 2022

Which Windows installation method requires the use of Windows deployment services (WDS)?
1. Network Installation
2. Repair Installation
3. Bootable flash drive installation
4. Unattended installation​

Answers

Answer:

1. Network Installation

Explanation:

Given

Options (1) to (4)

Required

Which requires WDS for installation

WDS are used for remote installations where users do not have to be physically present before installations can be done; in other words, it is necessary for network based installations.

Of all the given options, (a) is correct because without WDS, network installation cannot be done.

Use the tables below to show the difference between the results of a natural join, an equijoin (with PROF_CODE = 2) and a full outer join. Provide the resulting table of each join

Answers

Answer:

Code:

CREATE TABLE student (

stu_code INTEGER PRIMARY KEY,

prof_code INTEGER

);

INSERT INTO student VALUES (100278,null);

INSERT INTO student VALUES (128569,2);

INSERT INTO student VALUES (512272,4);

INSERT INTO student VALUES (531235,2);

INSERT INTO student VALUES (531268,null);

INSERT INTO student VALUES (553427,1);

CREATE TABLE professor (

prof_code INTEGER PRIMARY KEY,

dept_code INTEGER

);

INSERT INTO professor VALUES (1,2);

INSERT INTO professor VALUES (2,6);

INSERT INTO professor VALUES (3,6);

INSERT INTO professor VALUES (4,4);

The SQL NATURAL JOIN is a type of EQUI JOIN and is structured in such a way that, columns with the same name of associated tables will appear once only. In our Example, Prof_code will appear only once and it will be matched in both the table;  

SELECT * FROM Student natural join Professor on student.prof_code=Professor.prof_code ;  

Stud_code   Prof_code  Dept_code

128569        2           6

512272        4           4

531235        2           6

553427        1           2

EQUI JOIN performs a JOIN against equality or matching column(s) values of the associated tables and an equal sign (=) is used as a comparison operator in the where clause to refer to equality. In our example, it will only show the result with prof_code=2 from the natural join result.

SELECT * FROM Student join Professor on student.prof_code=Professor.prof_code where student.prof_code=2;

Stud_code Prof_code Prof_code Dept_code

128569     2         2         6

531235     2         2         6

In SQL the FULL OUTER JOIN combines the results of both left and right outer joins and returns all (matched or unmatched) rows from the tables on both sides of the join clause.

SELECT * FROM professor full outer join student on professor.prof_code=student.prof_code ;

Stud_code Prof_code Prof_code Dept_code

100278                

128569    2          2         6

512272    4          4         4

531235    2          2         6

531268    

                    3         6

553427    1          1         2

Write the code for the following problem.
Add a function to problem to display the last name and highest, last name and lowest and average exam score. Hint: for highest initialize a variable to 0 (high_var). If the array value is higher than the high_var then set high_var to the array value and set high_index to the position of the array. Proceed through the array until you get to the end. Do the same for finding the lowest using low_var set to 999 (higher than the highest value). For the average score, sum all the exam scores as you proceed through the loop. Use a for loop to go through each occurrence of the arrays. Note you can do all this with one for loop but if it makes more sense to you to use multiple for loops that is ok too.

Answers

Answer:

no

Explanation:

Carlos manages a Linux system that users are able to SSH into in order to perform certain tasks. However, he has just installed a critical patch and wants to reboot the server to ensure that it has fully taken effect. Which of the following commands should he use to ensure that a reboot will not interrupt any logged in users?

a. w
b. id
c. whoami
d. uname -a

Answers

The answer is "Option b" which is "id", and its further calculation can be defined as follows:

In the Linux system, the id command is being used to find out the account and main indicators and numeric IDs of a current user and any other user on the system. In this, command the User name and genuine user ID.It is used to list all the groups of which a user is a member, and also display the security context of the current user.

The wrong choice can be defined as follows:

In choice a, "w" is the use full command, which displays all users who are currently active.In choice c, "whoami" is used as our user name.In choice d, "uname-a" is used to shows information about the network.

Therefore "Choice b" is the correct answer.

Learn more:

Linux system: brainly.com/question/3133247

how do you copy a file​

Answers

Answer:

right click and press control c

explain how data structures and algorithms are useful to the use of computer in data management

Answers

Answer:

programmers who are competent  in data  structures and algorithms  can easily perform the tasks related  to data processing ,automated reasoning ,or calculations . data structure and algorithms  is significant  for developers  as it shows their problems solving abilities amongst the prospective employers .

A hammer tool can only be used by one technician at a time to perform hitting. Accordingly, you have developed a Hammer class with a hit method. Objects of class Hammer are used to simulate different hammers, while threads are created to simulate users. Which situation needs to add the synchronized keyword to the hit method

Answers

Answer:

Explanation:

The synchronized keyword needs to be active on the hit method at any point where 2 or more threads (users) exists at any given moment. This is in order to prevent two or more users from trying to perform a hammer hit at the same time. This is what the synchronized keyword is used for. It prevents the more than one thread from calling the specific method at the same time. Instead it adds the action to a sequence so that the second thread calls the hit method only after the first thread's hit method finishes.

Imagine that you wanted to write a program that asks the user to enter in 5 grade values. The user may or may not enter valid grades, and you want to ensure that you obtain 5 valid values from the user. Which nested loop structure would you use?
A. A "for" loop inside of a "while" loop
B. A "while" loop inside of a "for" loop
C. None of the above
D. Either a or b would work

Answers

The type of nested loop which I would use to write the program is:

B. A "while" loop inside of a "for" loop

What is a Loop?

This refers to the control flow statement which is used to iterate and lets a particular line(s) of code execute repeatedly

With this in mind, we can see that the type of nested loop which I would use to write the program is a "while" loop inside of a "for" loop because it is a conditional statement that continues to ask for the certain valid grades until it gets the right one.

Therefore, the correct answer is option B

Read more about loops here:
https://brainly.com/question/26098908

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