create sequence s_test
start with 1
increment by 1
minvalue 0
maxvalue 10;

create table sm_student(
id number primary key,
name varchar2(20));

insert into sm_student values(s_test.nextval,'Tomcat');
insert into sm_student values(s_test.nextval,'oracle');

---session2------------------
insert into sm_student values(s_test.nextval,'c++');
insert into sm_student values(s_test.nextval,'liunx');