Consider the relational schema below: Students(sid: integer, sname: string, major: string) Courses(cid: integer, cname: string) Enrollment(sid: integer, cid: integer, grade: real) Write a tuple relational calculus expression that satisfies this query? Find the distinct names of all students who major in either "Math" or "Economics" who score less than 60% in either course 91.573 or in course 14.601 (using cid).

Reading characters and strings from the keyboard: consider the following c++ program 1. #include 2. #include 3. using namespace std; 4. mystring1 5. 6. int main() 7. { 8. 9. string mystring1, mystring2; mychar1 10. 11. 12. char mychar1, mychar2; 13. 14. cout< < "enter a string: "; mychar2 15. 16. cin> > mystring1; // 17. cin. get(mychar1); 18. cin> > mychar2; 19. getline(cin, mystring2); mystring2 20. 21. 22. cout<

What is the first step in creating a maintenance ?

Which location-sharing service offers items for users as a gaming component and also allows them to collectively link their check-ins to publish a trip? a. whrrl b. buzzd c. foursquare (this option is wrong i already tried) d. gowalla for plato