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?Oracle??????????????????????????????ID?????????????????????????????

???????????seq_nc_user?????????ID?????1?????????1?

create sequence seq_nc_user
increment by 1
start with 1
nomaxvalue nocycle cache 10;

???????????nc_user???????ID???????????????????????ID???????????

create table nc_user (
    ncid number(9),
    name varchar2(50) not null,
    mail varchar2(50),
    pass varchar2(50),
    descb varchar2(255) default 'nice',
    age number(9)
);

??????ID???????????????????????????????????????????0?110???

alter table nc_user
add constraint pk_nc_user primary key(ncid);
alter table nc_user
add constraint uk_nc_user unique(name);
alter table nc_user
add constraint ck_nc_user check(age > 0 and age < 110);

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alter table nc_user
drop constraint pk_nc_user cascade;
alter table nc_user
drop constraint uk_nc_user cascade;
alter table nc_user
drop constraint ck_nc_user cascade;

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drop table nc_user;
create trigger tri_nc_user
before insert on nc_user for each row
begin
    select seq_nc_user.nextval into :new.ncid from dual;
end;
/
drop trigger tri_nc_user;

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