Notes

--checking the sequence
SELECT seq_company_id FROM companies;

--creating sequence
CREATE SEQUENCE seq_company_id
START WITH 90
INCREMENT BY 2
NOCYCLE;

--creating procedure named proc_add_company
CREATE OR REPLACE PROCEDURE proc_add_company IS
vc_company_name companies.company_name%TYPE := 'NEW COMPANY';

BEGIN
INSERT INTO companies(company_id,company_name)
VALUES(seq_company_id.NEXTVAL,vc_company_name);

END proc_add_company;
/
SHOW ERRORS;

--creating procedure named proc_delete_company
CREATE OR REPLACE PROCEDURE proc_delete_company IS
vn_company_id companies.company_id%TYPE;

BEGIN
SELECT seq_company_id.currval
INTO vn_company_id
FROM dual;

DELETE FROM companies
WHERE company_id=vn_company_id;

END proc_delete_company;
/
SHOW ERRORS;

--amending above code
CREATE OR REPLACE PROCEDURE proc_param_del_co(in_company_id IN companies.company_id%TYPE) IS

BEGIN
DELETE FROM companies
WHERE company_id=in_company_id;

END proc_param_del_co;
/
SHOW ERRORS;