symbol σ for SELECT, Π for PROJECT, for EQUIJOIN, * for NATURAL JOIN, and f forϑFUNCTION 1)EMP_WX <-- (σ Pname='ProductX'(PROJECT)) Π (Pnumber),(Pno)(WORKS_ON) EMP_WORK10 <-- (EMPLOYEE) (Ssn),(Essn) (σ HOURS>10(EMP_WX)) ϑFINAL <--Π Lname,Fname (σ DNO=5(EMP_WORK10))2)E <-- (EMPLOYEE) (Ssn,Fname),(Essn,DEPENDENT_NAME) (DEPENDENT)ϑR <-- Π Lname,Fname (E)3)WONG_SSN <-- Π Ssn (σ Fname='Franklin' AND Lname='Wong'(EMPLOYEE))WONG <-- (EMPLOYEE) (SUPERSSN),(Ssn) (WONG_SSN)ϑFINAL <-- Π Lname,Fname (WONG)4)PROJ_HOURS(Pno,TOT_HRS) <-- Pno f SUM HOURS(WORKS_ON)FINAL <-- Π Pname,TOT_HRS ( (PROJ_HOURS) (Pno),(Pnumber) (PROJECT) )ϑ5)PROJ_EMPS(Pno,Ssn) <-- Π Pno,Essn (WORKS_ON)ALL_PROJS(Pno) <-- Π Pnumber (PROJECT)EMP_ALLPROJS <-- PROJ_EMPS ÷ ALLPROJS FINAL <-- Π Lname,Fname (EMPLOYEE * EMP_ALLPROJS)6)ALL_EMPS <-- Π Ssn (EMPLOYEE)WORKING_EMPS(Ssn) <-- Π Essn (WORKS_ON)NON_WORKING_EMPS <-- ALL_EMPS - WORKING_EMPS FINAL <-- Π Lname,Fname (EMPLOYEE * NON_WORKING_EMPS)7)DEPT_AVG_SALS(DNUMBER,AVG_SAL) <-- DNO f AVG SALARY(EMPLOYEE)FINAL <-- Π DNUMBER,AVG_SAL ( DEPT_AVG_SALS * DEPARTMENT )8)FINAL(AVG_F_SAL) <-- f AVG SALARY(σ SEX='F'(EMPLOYEE) )9)E_P_HOU(Ssn) <-- Π Essn (WORKS_ON (Pno),(Pnumber)(σ ϑPLOCATION='Houston'(PROJECT)))D_NO_HOU <-- Π DNUMBER(DEPARTMENT) - Π DNUMBER(σ DLOCATION='Houston'(DEPARTMENT))E_D_NO_HOU <-- Π Ssn (EMPLOYEE (Pno),(DNUMBER)(D_NO_HOU))ϑFINAL_EMPS <-- E_P_HOU - E_D_NO_HOU FINAL <-- Π Lname,Fname,Address (EMPLOYEE * FINAL_EMPS)10)DEPT_MANAGERS(Ssn)<--Π MgrSsn (DEPARTMENT)EMPS_WITH_DEPENDENTS(Ssn) <-- Π Essn (DEPENDENT)FINAL_EMPS <-- DEPT_MANAGERS - EMPS_WITH_DEPENDENTSFINAL <-- Π Lname,Fname (EMPLOYEE *
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