外键约束失败 - 即使我尝试手动添加数据
Foreign Key Constraint Failed - Even when I try to manually add data
我正在攻读 SQL 我的数据科学学位课程，作业是第一次执行 SQL 查询。为此，我必须将 SQL 起始代码粘贴到 运行 中。但是，当我这样做时，我遇到了一个我无法解决的错误。我的 class 在线，我的教授没有回复，因为这不是作业的评分部分，我想我会尝试在这里获得有关此错误的帮助。
编辑：有人指出我没有包括所有表格。请查看所有表格和所有数据的完整代码。我试图避免用大量代码行淹没此 post，但似乎我遗漏了相关信息。见下文。
这些表是使用这些代码块创建的：
create table section (
course_id varchar(8),
sec_id varchar(8),
semester varchar(6) check (semester in ('Fall', 'Winter', 'Spring', 'Summer')),
year numeric(4,0) check (year >1701 and year < 2100),
building varchar(15),
room_number varchar(7),
time_slot_id varchar(4),
primary key (course_id, sec_id, semester, year),
foreign key (course_id) references course on delete cascade,
foreign key (time_slot_id) references timeslot on delete no action,
foreign key (building, room_number) references classroom on delete set null
);
create table teaches (
ID varchar(5),
course_id varchar(8),
sec_id varchar(8),
semester varchar(6),
year numeric(4,0),
primary key (ID, course_id, sec_id, semester, year),
foreign key (course_id, sec_id, semester, year) references section on delete cascade,
foreign key (ID) references instructor on delete set null
);
create table instructor (
ID varchar(5),
name varchar(20) not null,
dept_name varchar(20),
salary numeric(8,2) check (salary >10000),
primary key (ID),
foreign key (dept_name) references department on delete set null
);
然后，我将数据添加到 instructor 和 section 中，如下所示。旁注，我必须进入并手动将 time_slot_id 设置为主键以避免出错。
INSERT INTO classroom VALUES ('Innovation Hall', '101', 10);
INSERT INTO classroom VALUES ('Innovation Hall', '327', 30);
INSERT INTO classroom VALUES ('Exploratory Hall', '202', 20);
INSERT INTO classroom VALUES ('Research Hall', '302', 20);
INSERT INTO classroom VALUES ('Arts Center', '212B', 100);
INSERT INTO classroom VALUES ('Research Hall', '310', 30);
INSERT INTO classroom VALUES ('Innovation Hall', '121', 10);
INSERT INTO classroom VALUES ('Innovation Hall', '321', 20);
INSERT INTO classroom VALUES ('Arts Center', '120A', 100);
INSERT INTO classroom VALUES ('Exploratory Hall', '231', 20);
INSERT INTO classroom VALUES ('Innovation Hall', '220', 30);
INSERT INTO department VALUES ('CDS', 'Research Hall', 100000);
INSERT INTO department VALUES ('Music', 'Arts Center', 70000);
INSERT INTO department VALUES ('History', 'Arts Center', 50000);
INSERT INTO department VALUES ('Geography', 'Exploratory Hall', 60000);
INSERT INTO department VALUES ('Biology', 'Exploratory Hall', 85000);
INSERT INTO department VALUES ('Physics', 'Innovation Hall', 90000);
INSERT INTO department VALUES ('Math', 'Exploratory Hall', 55000);
INSERT INTO course VALUES ('CDS-101', 'Intro to CDS', 'CDS', 3);
INSERT INTO course VALUES ('CDS-130', 'Computing for Scientists', 'CDS', 3);
INSERT INTO course VALUES ('CDS-302', 'Databases', 'CDS', 3);
INSERT INTO course VALUES ('CDS-303', 'Data Mining', 'CDS', 3);
INSERT INTO course VALUES ('MUS-100', 'Fundamentals of Music', 'Music', 3);
INSERT INTO course VALUES ('HIS-101', 'History of Western Civilization', 'History', 3);
INSERT INTO course VALUES ('GGS-101', 'Major World Regions', 'Geography', 4);
INSERT INTO course VALUES ('BIO-101', 'Intro to Biology', 'Biology', 3);
INSERT INTO course VALUES ('BIO-301', 'Genetics', 'Biology', 4);
INSERT INTO course VALUES ('PHY-101', 'Intro to Physics', 'Physics', 3);
INSERT INTO course VALUES ('PHY-403', 'Quantum Mechanics', 'Physics', 4);
INSERT INTO course VALUES ('MAT-110', 'Probabilities', 'Math', 3);
INSERT INTO course VALUES ('MAT-114', 'Calculus', 'Math', 4);
INSERT INTO prereq VALUES ('CDS-130', 'CDS-101');
INSERT INTO prereq VALUES ('MAT-114', 'MAT-110');
INSERT INTO prereq VALUES ('PHY-403', 'PHY-101');
INSERT INTO prereq VALUES ('CDS-302', 'CDS-130');
INSERT INTO prereq VALUES ('CDS-302', 'PHY-403');
INSERT INTO prereq VALUES ('CDS-303', 'CDS-302');
INSERT INTO prereq VALUES ('CDS-303', 'MAT-114');
INSERT INTO instructor VALUES ('11111', 'Turing', 'CDS', 950000);
INSERT INTO instructor VALUES ('11112', 'Widom', 'CDS', 100000);
INSERT INTO instructor VALUES ('12121', 'Mozart', 'Music', 75000);
INSERT INTO instructor VALUES ('22222', 'Heraclitus', 'History', 65000);
INSERT INTO instructor VALUES ('12345', 'Eratosthenes', 'Geography', 55000);
INSERT INTO instructor VALUES ('54321', 'Crick', 'Biology', 88000);
INSERT INTO instructor VALUES ('33333', 'Newton', 'Physics', 80000);
INSERT INTO instructor VALUES ('44444', 'Euler', 'Math', 77000);
INSERT INTO instructor VALUES ('55555', 'Euclid', 'Math', 77000);
INSERT INTO timeslot VALUES ('A', 'M', 8, 0 , 9, 15);
INSERT INTO timeslot VALUES ('B', 'M', 10, 0 , 11, 15);
INSERT INTO timeslot VALUES ('C', 'T', 8, 0 , 9, 15);
INSERT INTO timeslot VALUES ('D', 'T', 10, 0 , 11, 15);
INSERT INTO timeslot VALUES ('E', 'T', 11, 15 , 12, 30);
INSERT INTO timeslot VALUES ('F', 'W', 9, 0 , 10, 15);
INSERT INTO timeslot VALUES ('G', 'R', 8, 0 , 10, 15);
INSERT INTO timeslot VALUES ('H', 'R', 15, 0 , 16, 15);
INSERT INTO timeslot VALUES ('I', 'F', 9, 0 , 10, 15);
INSERT INTO section VALUES ('CDS-101', '1', 'Fall', 2019, 'Research Hall', '310', 'A');
INSERT INTO section VALUES ('CDS-130', '1', 'Fall', 2019, 'Innovation Hall', '121', 'B');
INSERT INTO section VALUES ('CDS-302', '1', 'Fall', 2019, 'Innovation Hall', '327', 'C');
INSERT INTO section VALUES ('CDS-302', '2', 'Spring', 2019, 'Innovation Hall', '321', 'C');
INSERT INTO section VALUES ('MUS-100', '1', 'Fall', 2019, 'Arts Center', '120A', 'A');
INSERT INTO section VALUES ('HIS-101', '1', 'Fall', 2019, 'Arts Center', '212B', 'B');
INSERT INTO section VALUES ('GGS-101', '1', 'Fall', 2019, 'Exploratory Hall', '202', 'D');
INSERT INTO section VALUES ('BIO-101', '2', 'Fall', 2019, 'Exploratory Hall', '231', 'E');
INSERT INTO section VALUES ('PHY-403', '1', 'Spring', 2019, 'Innovation Hall', '220', 'F');
INSERT INTO section VALUES ('BIO-101', '2', 'Fall', 2020, 'Exploratory Hall', '231', 'C');
INSERT INTO section VALUES ('PHY-403', '1', 'Spring', 2020, 'Innovation Hall', '220', 'D');
我没有遇到问题。最后，我尝试 运行 这个：
INSERT INTO teaches VALUES ('11111', 'CDS-101', '1', 'Fall', 2019);
INSERT INTO teaches VALUES ('11112', 'CDS-130', '1', 'Fall', 2019);
INSERT INTO teaches VALUES ('12121', 'MUS-100', '1', 'Fall', 2019);
INSERT INTO teaches VALUES ('54321', 'BIO-101', '2', 'Fall', 2019);
INSERT INTO teaches VALUES ('33333', 'PHY-403', '1', 'Spring', 2019);
INSERT INTO teaches VALUES ('44444', 'MAT-114', '2', 'Fall', 2019);
错误发生在最后一行。我总是得到：
结果：FOREIGN KEY 约束失败
在第 1 行：（注意：之后我自己尝试 re-running，因此 "Line 1"）
INSERT INTO teaches VALUES ('44444', 'MAT-114', '2', 'Fall', 2019);
我检查了每个约束，查看了每一列，但无法弄清楚。我什至在 DB Browser Lite 的 "Browse Data" 选项卡中手动输入了数据；虽然我能够输入前 4 个值，但当我尝试输入年份的任何内容时，我会在弹出框中遇到相同的错误。即使当我在框中单击，将其留空，然后尝试单击退出时，我也会遇到同样的错误。见图。
请协助...我现在迷路了，非常沮丧。
这里有两件事：
- 问题，以及
- 如何找出问题所在。
让我们从 2) 开始。
错误信息是：
Result: FOREIGN KEY constraint failed
At line 1:
INSERT INTO teaches VALUES ('44444', 'MAT-114', '2', 'Fall', 2019);
这告诉我们要查看 teaches table 上定义的外键。
有2个：
- ID 引用 instructor table 中的 ID（顺便说一句：也许称这个 instructor_id 而不是 ID，6 周后你回来看它会更有意义）。
- course_id、sec_id、学期、年份参考 table.
部分
在您的数据中，有一位 ID 为“44444”的讲师，所以这可能不是问题所在。
但 section 中似乎没有与 'MAT-114', '2', 'Fall', 2019 的一行，这可能是您的问题。
另请注意，'MTH-114' 也没有像图片中那样。
我正在攻读 SQL 我的数据科学学位课程，作业是第一次执行 SQL 查询。为此，我必须将 SQL 起始代码粘贴到 运行 中。但是，当我这样做时，我遇到了一个我无法解决的错误。我的 class 在线，我的教授没有回复，因为这不是作业的评分部分，我想我会尝试在这里获得有关此错误的帮助。
编辑：有人指出我没有包括所有表格。请查看所有表格和所有数据的完整代码。我试图避免用大量代码行淹没此 post，但似乎我遗漏了相关信息。见下文。
这些表是使用这些代码块创建的：
create table section (
course_id varchar(8),
sec_id varchar(8),
semester varchar(6) check (semester in ('Fall', 'Winter', 'Spring', 'Summer')),
year numeric(4,0) check (year >1701 and year < 2100),
building varchar(15),
room_number varchar(7),
time_slot_id varchar(4),
primary key (course_id, sec_id, semester, year),
foreign key (course_id) references course on delete cascade,
foreign key (time_slot_id) references timeslot on delete no action,
foreign key (building, room_number) references classroom on delete set null
);
create table teaches (
ID varchar(5),
course_id varchar(8),
sec_id varchar(8),
semester varchar(6),
year numeric(4,0),
primary key (ID, course_id, sec_id, semester, year),
foreign key (course_id, sec_id, semester, year) references section on delete cascade,
foreign key (ID) references instructor on delete set null
);
create table instructor (
ID varchar(5),
name varchar(20) not null,
dept_name varchar(20),
salary numeric(8,2) check (salary >10000),
primary key (ID),
foreign key (dept_name) references department on delete set null
);
然后，我将数据添加到 instructor 和 section 中，如下所示。旁注，我必须进入并手动将 time_slot_id 设置为主键以避免出错。
INSERT INTO classroom VALUES ('Innovation Hall', '101', 10);
INSERT INTO classroom VALUES ('Innovation Hall', '327', 30);
INSERT INTO classroom VALUES ('Exploratory Hall', '202', 20);
INSERT INTO classroom VALUES ('Research Hall', '302', 20);
INSERT INTO classroom VALUES ('Arts Center', '212B', 100);
INSERT INTO classroom VALUES ('Research Hall', '310', 30);
INSERT INTO classroom VALUES ('Innovation Hall', '121', 10);
INSERT INTO classroom VALUES ('Innovation Hall', '321', 20);
INSERT INTO classroom VALUES ('Arts Center', '120A', 100);
INSERT INTO classroom VALUES ('Exploratory Hall', '231', 20);
INSERT INTO classroom VALUES ('Innovation Hall', '220', 30);
INSERT INTO department VALUES ('CDS', 'Research Hall', 100000);
INSERT INTO department VALUES ('Music', 'Arts Center', 70000);
INSERT INTO department VALUES ('History', 'Arts Center', 50000);
INSERT INTO department VALUES ('Geography', 'Exploratory Hall', 60000);
INSERT INTO department VALUES ('Biology', 'Exploratory Hall', 85000);
INSERT INTO department VALUES ('Physics', 'Innovation Hall', 90000);
INSERT INTO department VALUES ('Math', 'Exploratory Hall', 55000);
INSERT INTO course VALUES ('CDS-101', 'Intro to CDS', 'CDS', 3);
INSERT INTO course VALUES ('CDS-130', 'Computing for Scientists', 'CDS', 3);
INSERT INTO course VALUES ('CDS-302', 'Databases', 'CDS', 3);
INSERT INTO course VALUES ('CDS-303', 'Data Mining', 'CDS', 3);
INSERT INTO course VALUES ('MUS-100', 'Fundamentals of Music', 'Music', 3);
INSERT INTO course VALUES ('HIS-101', 'History of Western Civilization', 'History', 3);
INSERT INTO course VALUES ('GGS-101', 'Major World Regions', 'Geography', 4);
INSERT INTO course VALUES ('BIO-101', 'Intro to Biology', 'Biology', 3);
INSERT INTO course VALUES ('BIO-301', 'Genetics', 'Biology', 4);
INSERT INTO course VALUES ('PHY-101', 'Intro to Physics', 'Physics', 3);
INSERT INTO course VALUES ('PHY-403', 'Quantum Mechanics', 'Physics', 4);
INSERT INTO course VALUES ('MAT-110', 'Probabilities', 'Math', 3);
INSERT INTO course VALUES ('MAT-114', 'Calculus', 'Math', 4);
INSERT INTO prereq VALUES ('CDS-130', 'CDS-101');
INSERT INTO prereq VALUES ('MAT-114', 'MAT-110');
INSERT INTO prereq VALUES ('PHY-403', 'PHY-101');
INSERT INTO prereq VALUES ('CDS-302', 'CDS-130');
INSERT INTO prereq VALUES ('CDS-302', 'PHY-403');
INSERT INTO prereq VALUES ('CDS-303', 'CDS-302');
INSERT INTO prereq VALUES ('CDS-303', 'MAT-114');
INSERT INTO instructor VALUES ('11111', 'Turing', 'CDS', 950000);
INSERT INTO instructor VALUES ('11112', 'Widom', 'CDS', 100000);
INSERT INTO instructor VALUES ('12121', 'Mozart', 'Music', 75000);
INSERT INTO instructor VALUES ('22222', 'Heraclitus', 'History', 65000);
INSERT INTO instructor VALUES ('12345', 'Eratosthenes', 'Geography', 55000);
INSERT INTO instructor VALUES ('54321', 'Crick', 'Biology', 88000);
INSERT INTO instructor VALUES ('33333', 'Newton', 'Physics', 80000);
INSERT INTO instructor VALUES ('44444', 'Euler', 'Math', 77000);
INSERT INTO instructor VALUES ('55555', 'Euclid', 'Math', 77000);
INSERT INTO timeslot VALUES ('A', 'M', 8, 0 , 9, 15);
INSERT INTO timeslot VALUES ('B', 'M', 10, 0 , 11, 15);
INSERT INTO timeslot VALUES ('C', 'T', 8, 0 , 9, 15);
INSERT INTO timeslot VALUES ('D', 'T', 10, 0 , 11, 15);
INSERT INTO timeslot VALUES ('E', 'T', 11, 15 , 12, 30);
INSERT INTO timeslot VALUES ('F', 'W', 9, 0 , 10, 15);
INSERT INTO timeslot VALUES ('G', 'R', 8, 0 , 10, 15);
INSERT INTO timeslot VALUES ('H', 'R', 15, 0 , 16, 15);
INSERT INTO timeslot VALUES ('I', 'F', 9, 0 , 10, 15);
INSERT INTO section VALUES ('CDS-101', '1', 'Fall', 2019, 'Research Hall', '310', 'A');
INSERT INTO section VALUES ('CDS-130', '1', 'Fall', 2019, 'Innovation Hall', '121', 'B');
INSERT INTO section VALUES ('CDS-302', '1', 'Fall', 2019, 'Innovation Hall', '327', 'C');
INSERT INTO section VALUES ('CDS-302', '2', 'Spring', 2019, 'Innovation Hall', '321', 'C');
INSERT INTO section VALUES ('MUS-100', '1', 'Fall', 2019, 'Arts Center', '120A', 'A');
INSERT INTO section VALUES ('HIS-101', '1', 'Fall', 2019, 'Arts Center', '212B', 'B');
INSERT INTO section VALUES ('GGS-101', '1', 'Fall', 2019, 'Exploratory Hall', '202', 'D');
INSERT INTO section VALUES ('BIO-101', '2', 'Fall', 2019, 'Exploratory Hall', '231', 'E');
INSERT INTO section VALUES ('PHY-403', '1', 'Spring', 2019, 'Innovation Hall', '220', 'F');
INSERT INTO section VALUES ('BIO-101', '2', 'Fall', 2020, 'Exploratory Hall', '231', 'C');
INSERT INTO section VALUES ('PHY-403', '1', 'Spring', 2020, 'Innovation Hall', '220', 'D');
我没有遇到问题。最后，我尝试 运行 这个：
INSERT INTO teaches VALUES ('11111', 'CDS-101', '1', 'Fall', 2019);
INSERT INTO teaches VALUES ('11112', 'CDS-130', '1', 'Fall', 2019);
INSERT INTO teaches VALUES ('12121', 'MUS-100', '1', 'Fall', 2019);
INSERT INTO teaches VALUES ('54321', 'BIO-101', '2', 'Fall', 2019);
INSERT INTO teaches VALUES ('33333', 'PHY-403', '1', 'Spring', 2019);
INSERT INTO teaches VALUES ('44444', 'MAT-114', '2', 'Fall', 2019);
错误发生在最后一行。我总是得到：
结果：FOREIGN KEY 约束失败
在第 1 行：（注意：之后我自己尝试 re-running，因此 "Line 1"）
INSERT INTO teaches VALUES ('44444', 'MAT-114', '2', 'Fall', 2019);
我检查了每个约束，查看了每一列，但无法弄清楚。我什至在 DB Browser Lite 的 "Browse Data" 选项卡中手动输入了数据；虽然我能够输入前 4 个值，但当我尝试输入年份的任何内容时，我会在弹出框中遇到相同的错误。即使当我在框中单击，将其留空，然后尝试单击退出时，我也会遇到同样的错误。见图。
请协助...我现在迷路了，非常沮丧。
这里有两件事：
- 问题，以及
- 如何找出问题所在。
让我们从 2) 开始。
错误信息是：
Result: FOREIGN KEY constraint failed
At line 1:
INSERT INTO teaches VALUES ('44444', 'MAT-114', '2', 'Fall', 2019);
这告诉我们要查看 teaches table 上定义的外键。
有2个：
- ID 引用 instructor table 中的 ID（顺便说一句：也许称这个 instructor_id 而不是 ID，6 周后你回来看它会更有意义）。
- course_id、sec_id、学期、年份参考 table. 部分
在您的数据中，有一位 ID 为“44444”的讲师，所以这可能不是问题所在。
但 section 中似乎没有与 'MAT-114', '2', 'Fall', 2019 的一行，这可能是您的问题。
另请注意，'MTH-114' 也没有像图片中那样。