create table ywc_test
(
id integer not null ,
name varchar(50),
constraint ywc_test_pk primary key (id)
);

create sequence ywc_test_seq minvalue 1 maxvalue 99999999
increment by 1
start with 1;

create or replace trigger ywc_test_tri
before insert on ywc_test
for each row
begin
select ywc_test_seq.nextval into :new.id from dual;
end;

insert into ywc_test (name) values ('哈哈');

select * from ywc_test;

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