無法刪除或更新父行
我是新用戶。我想問一下我在作業項目中遇到的錯誤。我建立 room_type_id 這是房間類型表中的主鍵。然後，room_type_id 作為外鍵包含在房間表中。問題是，如果我將房間類型 ID 之一輸入為 RI2 而不是 RT2。當我嘗試在房間表中的更新查詢中更改它時，它顯示無法更新子行外鍵約束失敗。但是，它顯示無法更新父行，房間類型表中的外鍵約束失敗。我對我的英語感到抱歉，因為它不是我的主要語言
create table room_type ( room_type varchar(20) not null, room_type_id varchar(10) not null, primary key(room_type_id));
create table room ( room_no varchar(10) not null, building_id varchar(10) not null, room_type_id varchar(10) not null, room_price varchar(10) not null, primary key(room_no), foreign key (building_id) references building(building_id), foreign key (room_type_id) references room_type(room_type_id));
insert into room_type
values ('Standard Room', 'RT1'),
('Dulexe Room', 'RI2'),
('Super Dulexe Room', 'RT3'),
('Suite Room', 'RT4'),
('Super Suite Room', 'RT5'),
('Executive Suite Room', 'RT6'),
('Presidential Suite Room', 'RT7'),
('Family Room', 'RT8'),
('VIP Room', 'RT9'),
('Ceremony Hall 1', 'RT10'),
('Ceremony Hall 2', 'RT11'),
('Ceremony Hall 3', 'RT12'),
('Meeting Conference Room 1', 'RT13'),
('Meeting Conference Hall 1', 'RT14'),
('Meeting COnference Hall 2', 'RT15');
insert into room
values ('R101', 'B1', 'RT1', '0'),
('R102', 'B1', 'RT1', '0'),
('R103', 'B1', 'RT1', '0'),
('R107', 'B1', 'RI2', '0'),
('R108', 'B1', 'RI2', '0'),
('R1011','B1', 'RT3', '0'),
('R1012','B1', 'RT3', '0'),
('R1013','B1', 'RT3', '0'),
('R1014','B1', 'RT3','0'),
('R501', 'B5', 'RT4', '0'),
('R502', 'B5', 'RT4', '0'),
('R505', 'B5', 'RT5', '0'),
('R506', 'B5', 'RT5', '0'),
('R601', 'B6', 'RT4', '0'),
('R602', 'B6', 'RT4', '0'),
('R605', 'B6', 'RT5', '0'),
('R606', 'B6', 'RT5', '0'),
('R701', 'B7', 'RT6', '0'),
('R702', 'B7', 'RT6', '0'),
('R801', 'B8', 'RT7', '0'),
('R802', 'B8', 'RT7', '0'),
('R901', 'B9', 'RT8', '0'),
('R902', 'B9', 'RT8', '0'),
('R1001','B10','RT9', '0'),
('R1002','B10','RT9', '0'),
('R1101','B11','RT10', '0'),
('R1102','B11','RT11', '0'),
('R1103','B11','RT12', '0'),
('R1201','B12','RT13', '0'),
('R1202','B12','RT14', '0'),
('R1203','B12','RT15', '0');
Update room set room_type_id='RT2' where room_no='R107';
Update room set room_type_id='RT2' where room_no='R108', building_id='B1';
Update room_type set room_type_id = 'RT2' where room_type='Dulexe Room';
