Query 0: Retrieve the birthdate and address of the employees whose name is "John B. Smith".

{ u,v | (exists t,w,x,y,z)(
            employee('John','B','Smith',t,u,v,w,x,y,z) ) }

Query 1: Retrieve the name and address of all employees who work for the "Research"
department.

{ q,s,v | (exists r,t,u,w,x,y,z,n,o)(
            employee(q,r,s,t,u,v,w,x,y,z) and 
            department('Research',z,n,o) ) }

Query 2: For every project located in "Stafford", list the project number, the 
controlling department number, and the department manager's last name, 
birth date, and address.

{ i,k,s,u,v | (exists h,q,r,t,w,x,y,z,l,o)(
                projects(h,i,'Stafford',k) and 
                employee(q,r,s,t,u,v,w,x,y,z) and 
                department(l,k,t,o) ) }

Query 6: List the names of employees who have no dependents.

{ q,s | (exists r,t,u,v,w,x,y,z)(
          employee(q,r,s,t,u,v,w,x,y,z) and 
          not ((exists m,n,o,p)(dependent(t,m,n,o,p))) ) }

The following is not SAFE and would not work

{ q,s | (exists r,t,u,v,w,x,y,z)(
          employee(q,r,s,t,u,v,w,x,y,z) and 
         (forall l,m,n,o,p)(not (dependent(l,m,n,o,p)) or t<>l) )}

Query 7: List the names of managers who have at least one dependent.

{ s,q | (exists r,t,u,v,w,x,y,z,h,i,k,m,n,o,p)(
           employee(q,r,s,t,u,v,w,x,y,z) and 
           department(h,i,t,k) and
           dependent(t,m,n,o,p) ) }