CREATE TABLE emp (empno NUMBER, ename VARCHAR2(10))

INSERT INTO emp VALUES(7839, 'King')

INSERT INTO emp VALUES(7698, 'Blake')

INSERT INTO emp VALUES(7782, 'Clark')

COMMIT

CREATE OR REPLACE PROCEDURE log_execution IS 
BEGIN 
  DBMS_OUTPUT.PUT_LINE('log_execution: Emp table has inserted 1 row.'); 
END; 

Creating a trigger where calls the previous procedure 'log_execution'.

CREATE OR REPLACE TRIGGER log_emp 
BEFORE INSERT ON emp 
FOR EACH ROW 
CALL log_execution -- no semicolon needed 

CREATE OR REPLACE TRIGGER log_emp 
BEFORE INSERT ON emp 
FOR EACH ROW 
CALL log_execution 

INSERT INTO emp VALUES(7566, 'Jones')

COMMIT