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Relational Algebra expression and relational domain calculus
Bid Request Id: 9701
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Posted by: |
salapaw (6 ratings)
(Software buyer rating 9.83 )
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Posted: |
Feb 27, 2002
8:02:11 AM EDT
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Bidding Closes: |
Mar 1, 2002
1:00:00 PM EDT
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Viewed (by coders): |
120 times
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Description:
Relational algebra expression and domain calculus expression.
Should be a rather quick job.
Deliverables:
Consider the following relational database schema:
student (StudentID, StudentName, Major)
Primary Key: {StudentID}
Candidate Key: {StudentID}
Foreign Key: {}
course (CourseNum, CourseName, Instructor)
Primary Key: {CourseNum}
Candidate Key: {CourseNum}
Foreign Key: {}
takes (StudentID, CourseNum)
Primary Key: {StudentID, CourseNum}
Candidate Key: {StudentID, CourseNum}
Foreigh Key: {StudentID}
referencing relation: takes
referenced relation: student
targeted candidate key: {StudentID}
{CourseNum}
referencing relation: takes
referenced relation: course
targeted candidate key: {CourseNum}
Express the following queries on the above schema in both relational algebra and relational domain calculus:
1. Find names and IDs of all students whose major is Computer Science.
2. Find all courses (CourseNum and CourseName) taught by Peter Peterson.
3. Find all courses (CourseNum only) taken by student John Johnson.
4. Find names of all instructors who teach courses taken by John Johnson.
5. Find names of all students who take at least one course taught by Peter Peterson
but take no course from David Davidson.
6. Find StudentIDs of the students who take all courses taught by David Davidson.
(Give only a relational algebra expression.)
7. Find all instructors who currently teach at least two courses. (Give only a
relational algebra expression.)
Platform:
word or in writting and later scanned in.
Special Conditions / Other:
done by March 1 before noon US Mountain time
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Bidding/Comments:
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Bid Amount
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Date |
Coder Rating |
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This bid was accepted by the buyer!
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$4 (USD)
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Feb 27, 2002
9:54:49 AM EDT
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9.6
(Excellent)
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| Your requirements can be fulfilled within given time. |
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