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CHAPTER 3 Relations
Students
SocSecNo
Name
Major
Class Year
247617832
Smith, John
Mathematics
2005
477677251
Brown, Mae
English
2006
149867253
Cyr, Pete
Mathematics
2005
316719842
Williams, Sue English
2004
Grades
SocSecNo
CourseCode Grade
316719842 Math2l1
A
247617832 Engll03
B
149867253
Math214
A
149867253
Engll03
A
316719842
Math3l8
B
316719842
Eng1224
A
Catalog
CourseCode Department Credits
Math2l1
Mathematics
4
Engl 103
English
3
Math214
Mathematics
3
Math318
Mathematics
4
Eng1224
English
3
6. Find the join of Grades and Catalog.
7. Find the join of Students and Grades.
8. Find the join of Students, Grades, and Catalog.
9. Find all students who received an A in a course.
10. Find the department and number of credits for any course in which a student received
an A.
11. Find all second-year students who received an A.
12. Find the departments in which a student received an A in one of that department's
courses.
U Chapter Review
The idea of a relation gives a format for studying mathematical and nonmathematical relationships. Forming the composition of relations and defining the inverse of a relation
are fundamental operations on relations. The common properties of relations such as =,
<, and C are abstracted to define what it means for a relation to be reflexive, irreflexive,
symmetric, antisymmetric, and transitive. Finding the reflexive, symmetric, or transitive
closure of a relation identifies the smallest relation containing a given relation with a given