LAB 4 FIGURES

EMPLOYEE TABLE

PROJECT TABLE

DEPARTMENT TABLE

DEPENDENT TABLE

WORKS_ON TABLE

DEPT_LOCATIONS TABLE

RENAMING OPERATION Note : Ssn shouldn’t be underlined.

UNION OPERATION

UNION OPERATION

INTERSECTION OPERATION

SET DIFFERENCE (OR MINUS)

CARTESIAN PRODUCT

CARTESIAN PRODUCT

CARTESIAN PRODUCT

JOIN OPERATION

NATURAL JOIN OPERATION

NATURAL JOIN

LEFT OUTER JOIN

LEFT OUTER JOIN

RIGHT OUTER JOIN

DIVISION OPERATION

AGGREGATE FUNCTIONS ᵨ R(Dno,No_of_employees,Average_sal)(Dno COUNT Ssn, AVERAGE Salary(EMPLOYEE)) No renaming :

AGGREGATE FUNCTIONS ᵨ R(Dno,No_of_employees,Average_sal)(Dno COUNT Ssn, AVERAGE Salary(EMPLOYEE)) No grouping :

QUERY 1 Retrieve the name and address of all employees who work for the ‘Research’ department.

QUERY 1 RESEARCH_DEPT <- σ Dname=’Research’ (DEPARTMENT) RESEARCH_EMPS <- (RESEARCH_DEPT Dnumber=Dno EMPLOYEE) RESULT <- ∏ Fname, Lname, Address (RESEARCH_EMPS) OR ∏ Fname, Lname, Address (σ Dname=’Research’(DEPARTMENT Dnumber=Dno (EMPLOYEE)))

QUERY 2 List the names of employees with two or more dependents.

QUERY 2 T1(Ssn, No_of_dependents) <- Essn COUNT Dependent_name (DEPENDENT) T2 <- σ No_of_dependents>2 (T1) RESULT <- ∏ Lname, Fname (T2 * EMPLOYEE)

QUERY 3 Find the names of employees who work on all the projects controlled by department number 5.

QUERY 3 DEPT5_PROJS <- ᵨ(Pno)(∏ Pnumber (σ Dnum=5(PROJECT))) EMP_PROJ <- ᵨ(Ssn,Pno)(∏ Essn,Pno(WORKS_ON))

QUERY 3 RESULT_EMP_SSNS <- EMP_PROJ  DEPT5_PROJS RESULT <- ∏ Lname, Fname (RESULT_EMP_SSNS * EMPLOYEE)

QUERY 4 List the names of managers who have at least one dependent.

QUERY 4 MGRS(Ssn) <- ∏ Mgr_ssn (DEPARTMENT) EMPS_WITH_DEPS(Ssn) ∏ Essn (DEPENDENT) MGRS_WITH_DEPS <- (MGRS ∩ EMPS_WITH_DEPS) RESULT <- ∏ Lname, Fname (MGRS_WITH_DEPS * EMPLOYEE)