Consider the global relations EMP(ENAME, TITLE, CITY) and ASG(ENAME, PNAME, CITY, DUR). City in ASG is the location of the project of name PNAME (i.e., PNAME functionally determines CITY). Consider the local relations EMP1(ENAME, TITLE, CITY), EMP2(ENAME, TITLE, CITY), PROJ1(PNAME, CITY), PROJ2(PNAME, CITY) and ASG1(ENAME, PNAME,DUR). Consider query Q which selects the names of the employees assigned to a project in Rio de Janeiro for more than 6 months and the duration of their assignment. (a) Assuming the GAV approach, perform query rewriting. (b) Assuming the LAV approach, perform query rewriting using the bucket algorithm.

(subject distributed database)