DatabaseManagementSystems/Practical/Practical Exam/PL-SQL/P5 - PL-SQL Block.md

P5 - PL-SQL Block

Problem Statement: Write a PL/SQL Block to increase the salary of employees by 10% of existing salary, who are having salary less than average salary of organization, whenever such salary updates take place, a record for same is maintained in the increment_salary table. emp(emp_no, salary) increment_salary(emp_no, salary)

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Creating tables:

CREATE TABLE emp(
    emp_no NUMBER(14),
    salary NUMBER(14)
);

CREATE table increment_salary(
    emp_no NUMBER(14),
    salary NUMBER(14)
);

Inserting values:

INSERT INTO emp VALUES (1, 1000);
INSERT INTO emp VALUES (2, 8000);
INSERT INTO emp VALUES (3, 2000);
INSERT INTO emp VALUES (4, 5000);
INSERT INTO emp VALUES (5, 7000);

Procedure

DECLARE
    avg_salary NUMBER(14, 4);
BEGIN
    SELECT AVG(salary) INTO avg_salary FROM emp;
    FOR emp_record IN (select emp_no, salary FROM emp WHERE salary < avg_salary)
    LOOP
        insert into increment_salary(emp_no, salary) values (emp_record.emp_no, emp_record.salary);
        UPDATE emp SET salary = emp_record.salary * 1.10 WHERE emp_no = emp_record.emp_no;
    END LOOP;
EXCEPTION
    WHEN OTHERS THEN
        DBMS_OUTPUT.PUT_LINE('Error: ' || SQLERRM);
end;
/

OUTPUT: After PL/SQL Block:

emp:
EMP_NO SALARY
1 1100
2 8000
3 2200
4 5000
5 7000

increment_emp:
EMP_NO SALARY
1 1000
3 2000

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