alter table Worker_Tbl drop constraint PK_worker_TBL;drop table Worker_Tbl;drop procedure update_worker_salary;drop function update_worker_salary_func;drop sequence worker_id_seq;drop function add_worker_func;create sequence worker_id_seq increment by 1 start with 1;create table Worker_Tbl (id number(9)  not null, fname varchar(10)                     not null,lname varchar(10)                       not null, sex varchar(6),                       age number(5,2), birthday date, salary number(10, 5), createtime date                    not null,constraint PK_worker_TBL primary key (id));INSERT INTO Worker_Tbl(id, fname, lname, sex, age, birthday, salary, createtime) VALUES(100, 'Alan', 'Liu', 'male', 30, to_date('1975-12-07','yyyy/mm/dd'), 2000.32, sysdate);INSERT INTO Worker_Tbl(id, fname, lname, sex, age, birthday, salary, createtime) VALUES(200, 'Kevin', 'Ding', 'male', 32, to_date('1973-6-26','yyyy/mm/dd'), 1000.32, sysdate);INSERT INTO Worker_Tbl(id, fname, lname, sex, age, birthday, salary, createtime) VALUES(300, 'Larry', 'Zhao', 'male', 40, to_date('1965-12-07','yyyy/mm/dd'), 2100.32, sysdate);INSERT INTO Worker_Tbl(id, fname, lname, sex, age, birthday, salary, createtime) VALUES(400, 'George', 'Zhu', 'male', 35, to_date('1970-12-07','yyyy/mm/dd'), 2000.32, sysdate);commit;create procedure update_worker_salary(    p_id in Worker_Tbl.id%type,    p_factor    in Number)as worker_count integer;begin    select count(*) into worker_count from worker_Tbl where id = p_id;    if worker_count = 1 then        update worker_Tbl set salary = salary * p_factor;        commit;    end if;end update_worker_salary;/create function add_worker_func(    p_id        in  worker_Tbl.id%type,    p_fname     in  worker_Tbl.fname%type,    p_lname     in  worker_Tbl.lname%type,    p_sex       in  worker_Tbl.sex%type,    p_age       in  worker_Tbl.age%type,    p_birthday  in  worker_Tbl.birthday%type,    p_salary    in  worker_Tbl.salary%type,    p_createtime    in  worker_Tbl.createtime%type)as count integer;begin    select count(*) into count from worker_Tbl where id = p_id;    if count > 0 then        count = 0;        return count;    else        insert into worker_Tbl (id, fname, lname, sex, age, birthday, salary, createtime)         values (p_id, p_fname, p_lname, p_sex, p_age, p_birthday, p_salary, p_createtime);        commit;        count = 1;        return count;    end if;    end add_worker_func;/create function update_worker_salary_func(    p_id in  worker_Tbl.id%type,    p_factor   in  number) return integer as worker_count integer;begin        select count(*) into worker_count from worker_Tbl where id = p_id;                if worker_count = 0 then            return 0;        else            update worker_Tbl set salary = salary * p_factor;            commit;            return 1;        end if;end update_worker_salary_func;/