Question Part $(50$ points$)$

$(24$ points$)$ Consider the following relations, where the primary keys are underlined.

Employee $($eid$,$ ename, age, sup$\_$eid$)$

WorkOn $($eid$,$ pid, date$)$

Project $($pid$,$ pname, budget, lid$)$

Location$($lid$,$ street$\_$name, city, state, zip$\_$code$)$

Employee.sup$\_$eid refers to Employee.eid, WorkOn.eid refers to Employee.eid, WorkOn.pid refers to

Project.pid, and Project.lid refers to Location.lid.

Let E be Employee, let W be WorkOn, let P be Project, and let L be Location.

Write the relational algebra for the following queries.

$(3$ points$)$ List the names of employees who worked on the 'Database' project.

$(3$ points$)$ List the names of employees who worked on the project located in the city of 'Boca'.

$(3$ points$)$ List the names of employees who worked on the 'Database' project, but never worked

on the 'Data Mning' project.

$(3$ points$)$ List the names of employees who never worked on the project located in the city of

'Boca'.

$(3$ points$)$ List the names of employees who worked on the same project as their supervisor.

$(3$ points$)$ List the names of employees who worked on the same project on different dates

$(3$ points$)$ List the names of employees who worked on all the project located in the city of 'Boca'.

$(3$ points$)($Do not use the aggregation function$)$ List the names of the oldest employees.