1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
maxonik [38]
3 years ago
9

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".
Computers and Technology
1 answer:
daser333 [38]3 years ago
7 0

Solution :

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

Use NATURAL JOIN operator \Join 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.

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

You might be interested in
after installing a secondary hard drive what needs to be done to the hard drive and what do these two task do?
gladu [14]
Keep the first hard drive then override it insert the second one and memory goes into the second one
8 0
3 years ago
A _ is the acknowledgment of a potential noncomformity, or an opinion regarding an issue that is not covered by a standard
sleet_krkn [62]
Assumption - hope this helped took the test and got 100
5 0
2 years ago
Who conceptualizes the design and the working of a website
Citrus2011 [14]
Answer is "Web Designer".

Web Designers are the "artists" of the website. They conceptualize the layout and functionality of the site, from features to format. They may do little coding, and are mostly involved in the creative elements of web design. The Web Developer is less big-picture, and more knitty-gritty building of the website. She is the one who does the coding and actually builds the website, using the web designer's model. 
3 0
3 years ago
Harry is undertaking a digital photography course as the college and wants to
Ludmilka [50]

C. Unconventionally yes it will break down the system potentially causing a virus

4 0
2 years ago
Why was the microchip essential to improving computers?
-BARSIC- [3]
Because it downsized the scale of the computer itself.

5 0
3 years ago
Other questions:
  • PLEASE HELP PROGRAMMING WILL GIVE BRAINLIEST
    7·1 answer
  • How read binary file in c++
    7·1 answer
  • I need help on this ASAP, worth 93 points
    6·2 answers
  • To defragment a disk means to ____. slow it down, diagnose problems with it, reorganize it, repair it
    8·1 answer
  • San Diego broker Cal Abrams has avoided the technological trend of the past 20 years. Finally, he's jumped online and realized w
    14·1 answer
  • Suppose you have the following declaration.char[] nameList = new char[100];Which of the following range is valid for the index o
    7·1 answer
  • A debugging process where you, the programmer, pretend you are a computer and step through each statement while recording the va
    11·1 answer
  • What does the revolver do computer science​
    9·1 answer
  • PLEASE HELP ITS CODING AND I INCLUDED A SCREENSHOT OF WHAT TO DO
    14·1 answer
  • Some hackers are skillful computer operators, but others are younger inexperienced people who experienced hackers refer to as?
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!