Schema
student (rollNo, name, degree, year, sex, deptNo, advisor)
course (courseId, cname, credits, deptNo)
enrollment (rollNo, courseId, sem, year, grade)
Obtain the names of courses enrolled by student named Mahesh
{c.name | course(c) ^
(∃s) (∃e) ( student(s) ^ enrollment(e)^ s.name = “Mahesh”^ s.rollNo= e.rollNo^ c.courseId = e.courseId) }
Do we really need (∃s) (∃e) ? Can the query be like:
{c.name | course(c) ^
enrollment(e) ^
student(s) ^
c.courseId = e.courseId ^
e.rollNo = s.rollNo ^
s.name = "Mahesh" }
Are both correct?