Question

我想做什么 BEFORE INSERT触发器涉及到患者表旨在禁止将两名患者分配到同一房间他们的年龄差异大于10年。此外，触发器也是应该禁止两名允许年龄的患者被分配到同一张床上。

CREATE TABLE CODE
set linesize 130;
set pagesize 100;
drop table patient cascade constraints;
create table patient (pat_id char(7), 
pat_name varchar(41) constraint nn_patnm not null,
pat_gender char(1),
pat_age number(2) constraint nn_patage not null,
pat_admit_dt date constraint nn_patadmdt not null,
pat_wing char(1),
pat_room# number,
pat_bed char(1),
constraint pk_pat primary key (pat_id),
constraint chk_gender check (pat_gender in ('M', 'F')),
constraint chk_age check (pat_age between 1 and 90),
constraint chk_bed check(pat_bed in ('A', 'B')));
insert into patient values ('DB77642', 'Davis, Bill', 'M', 38, '14-DEC-2017', 'A', 16, 'A');
insert into patient values ('GD72222', 'Grimes, David', 'M', 23, '14-DEC-2017', 'B', 17, 'A');
insert into patient values ('LH97384', 'Lisauckis, Hal', 'M', 28, '14-DEC-2017', 'B', 17, 'B');
insert into patient values ('RN31679', 'Robbins, Nancy', 'F', 23, '14-DEC-2017', 'A', 20, 'A');
insert into patient values ('HR32343', 'Howell, Sue', 'F', 20, '14-DEC-2017', 'A', 21, 'B');
desc patient
select * from patient;
commit;

我正在使用LIST测试触发器

column pat_name format a18
column pat_gender format a10
column pat_admit_dt format a13
column pat_wing format a8
column pat_bed format a8
set feedback on
insert into patient values ('AZ24523', 'Zhou, Alicia', 'F', 24, '14-DEC-2016', 'A', 20, 'B');
select * from patient;
insert into patient values ('JA33234', 'Abbott, John', 'M', 50, '14-DEC-2016', 'A', 16, 'B');
select * from patient;
insert into patient values ('AN32676', 'Newman, Andrew', 'M', 10, '14-DEC-2016', 'A', 16, 'B');
select * from patient;
insert into patient values ('ZZ24523', 'Zhang, Zhaoping', 'F', 38, '14-DEC-2016', 'A', 16, 'A');
select * from patient;
insert into patient values ('PS76234', 'Savant, Priyanka', 'F', 21, '14-DEC-2016', 'A', 21, 'B');
select * from patient;
insert into patient values ('SS43823', 'Sundar, Sarayu', 'F', 24, '14-DEC-2016', 'A', 21, 'A');
select * from patient;
insert into patient values ('PM43453', 'Perrin, Michael', 'M', 43, '14-DEC-2016', 'B', 22, 'A');
select * from patient;

TRIGGER

create or replace trigger patient_ins_row
before insert on patient
for each row

declare
room_age number;
difference number;
pat_name1 varchar2(41);
pat_bed1 char(1);
pat_room1 number;
ERROR_MESSAGE EXCEPTION;
BEGIN

select pat_name, pat_age, pat_room#, pat_bed into pat_name1, room_age, pat_room1, pat_bed1
from patient where pat_room# = :new.pat_room#;
if (:new.pat_bed = pat_bed1)
then DBMS_OUTPUT.PUT_LINE ('Cannot Assign ' || :new.pat_name || ' to bed already occupied ' || :new.pat_room# || 'years');
else
difference := :new.pat_age - room_age;
end if;

if (difference > 10)
then RAISE ERROR_MESSAGE;
elsif (difference < 10) then
DBMS_OUTPUT.PUT_LINE ('New Patient: ' || :new.pat_name || ' is too young: age difference is ' || difference || 'years');
else
dbms_output.put_line ('Successful insertion of ' || :new.pat_name || 'in room' || pat_room1);
END IF;

EXCEPTION
WHEN ERROR_MESSAGE THEN
RAISE_APPLICATION_ERROR (-20001, 'New Patient: ' || :new.pat_name || ' is too old: age difference is ' || difference || 'years');
END;

我的标题中不断出现许多插入错误。不知道我做错了什么。

Answer 1

问题ORA-01422因此声明而引发：

select pat_name, pat_age, pat_room#, pat_bed 
  into pat_name1, room_age, pat_room1, pat_bed1
  from patient where pat_room# = :new.pat_room#;

因为，您的连续语句会尝试从重复使用的pat_room1中选择:new.pat_room#，其中16和21等值。{/ p>

例如，在您应用

时的测试集中

insert into patient values ('JA33234', 'Abbott, John', 'M', 50, '14-DEC-2016', 'A', 16, 'B');

上述选择会为16的值:new.pat_room#提供多行，并且too_many_rows错误将会提升。

ORA-01422：精确提取返回超过请求的行数触发错误

1 个答案: