Question
This Question is from Database Systems course .. Please need you answer be clear.. Please post answer not private web or tutorial..
The foltowing tables form part of a database held in an RDBMS: Employee (empNo, fName, IName, address, DOB, sex, position, deptNo) Department (deptNo, deptName, mgrEmpNo) Project (prpjNo, projName, deptNo) WorksOn (empNo, ProiNo. dateWorked. hoursWorked) where Employee contains employee details and empNo s the key. Department contains department details and deptNo s the key. mgrEmpNo identifies the employee who is the manager of the department. There is only one manager for each department. Project contains delays of the projects in each department and the key is projNo (no two departments can run the same project), and WorksOn contains delays of the hours worked by employees on each project, and empNo/projNo/dateWorked form the key. Using Relational Algebra, answer the following questions: List all of the departments Produce a list of the details of hours worked by employees (empNo, projNo, dateWorked, hoursWorked), but only of those who have worked more than 40 hours List only the first name and last of employees who have worked more than 40 hours. List all of the employees List all of the employees who are female List the names and addresses of all employees who are managers. In other words, you need to verify the position attribute. Produce a list of the names and addresses of all employees who work for the IT department, in which there should be at least once instance from the Department relation.
Explanation / Answer
1) select distinct deptname from department;
2)
1)select e.fName, e.lName from WorksOn t, Employee e where e.empNO=t.empNo and hoursWorked >40;
2)select e.fName, e.lName from WorksOn t, Employee e where e.empNO=t.empNo and hoursWorked >40 and sex like '%female%';
3)select e.fName, e.lName, e.address from WorksOn t, Employee e where e.empNO=t.empNo and hoursWorked >40 and position like '%managers%';
4)select e.fName, e.lName from WorksOn t, Employee e where e.empNO(+)=t.empNo and hoursWorked >40 and t.deptName like '%IT%';
