GATE CSE 2007
Q51.
Consider the following schedules involving two transactions. Which one of the following statements is TRUE? S_1 :r_1(X); r_1(Y); r_2(X); r_2(Y); w_2(Y); w_1(X) S_2 :r_1(X); r_2(X); r_2(Y); w_2(Y); r_1(Y); w_1(X)Q53.
Consider the relation employee(name, sex, supervisorName) with name as the key. supervisorName gives the name of the supervisor of the employee under consideration. What does the following Tuple Relational Calculus query produce?