sequence序列的使用

    　　create sequence seq_test 
   　　 increment by 2
   　　 start with 45
   　　 maxvalue 60
　　    cycle
  　　  nocache;

　　　create table t_user(
        id number,
        name varchar2(50) constraint user_name_nn not null,
        email varchar2(50),
        gender char(1),
        age number,
        birthday date,
        constraint user_id_pk primary key(id),
        constraint user_email_un unique(email),
        constraint user_gender_ck check(gender in(‘f‘,‘m‘))
    );
    create sequence t_user_seq;
    insert into t_user(id,name,salary) values(t_user_seq.nextval,‘tom‘,600);