Homework #5, CSc 498/698, Spring 1998


(1) Express the following queries in Tuple Relational Calculus.

    (a) Get the SSNs of employees who work for a project in which their
        supervisor also works.

    (b) Get the SSNs of employees who do not work for any projects
        located in "Houston".

    (c) Get the SSNs of employees who work on AT LEAST those projects
        on which the employee with SSN = 123456789 works.

    (d) Get the SSNs of employees who work on EXACTLY those projects
        on which the employee with SSN = 123456789 works.

    (e) Get the SSNs of employees who work on AT MOST those projects
        on which the employee with SSN = 123456789 works.