Person_URA(ssn, empid, name, hdate, phone, email, dept, manager);

pk_{ssn} Person_URA;
mvd_{ssn, phone} Person_URA;
mvd_{ssn, email} Person_URA;
fd_{empid, hdate} \select_{defined(empid) and defined(hdate)} Person_URA;
fd_{empid, dept} \select_{defined(empid) and defined(hdate) and defined(dept) and defined(manager)} Person_URA;
fd_{dept, manager} \select_{defined(empid) and defined(hdate) and defined(dept) and defined(manager)} Person_URA;
inc⊆_{manager, empid} (Person_URA, Person_URA);
