Log of Changes made in the Employee Table

CREATE TABLE Employee(
    emp_id                  VARCHAR2(20)    NOT NULL PRIMARY KEY,
    name                    VARCHAR2(20),
    salary                  NUMBER(10),
    dept_no                 NUMBER(10)
);
ALTER TABLE EMPLOYEE ADD CONSTRAINT input CHECK(regexp_like(emp_id, '[A-Z][A-Z][A-Z]'));
CREATE TABLE logEmp(
    emp_id                  VARCHAR2(20),
    change                  VARCHAR2(20),
    old_salary              NUMBER(10),
    username                VARCHAR2(20),
    change_date             DATE
);
CREATE OR REPLACE TRIGGER Insertion AFTER INSERT ON Employee FOR each ROW
BEGIN
    INSERT INTO logEmp VALUES(:NEW.emp_id, 'Insert', :old.salary, 'Shail', SYSDATE);
END;
/
CREATE OR REPLACE TRIGGER Updation before UPDATE ON Employee FOR each ROW
BEGIN
    INSERT INTO logEmp VALUES(:old.emp_id, 'Update', :old.salary, 'Shail', SYSDATE);
END;
/
CREATE OR REPLACE TRIGGER Deletion before DELETE ON Employee FOR each ROW
BEGIN
    INSERT INTO logEmp VALUES(:old.emp_id, 'Delete', :old.salary, 'Shail', SYSDATE);
END;
/
INSERT INTO Employee VALUES('AAA', 'ABC XYZ', 4000, 12);
UPDATE Employee SET salary = 5000 WHERE emp_id = 'AAA';
DELETE FROM Employee WHERE emp_id = 'AAA';
SELECT * FROM logEmp;