MYSQL外鍵錯誤：150無法創建表

我一直在閱讀有關StackOverflow和各種論壇關於這個問題，但我似乎無法弄清楚。當試圖運行下面的「CREATE TABLE Class」和「CREATE TABLE Enroll」命令時，我得到「ERROR 1005：Can not create table university.class（errno：150）」。我使用InnoDB作爲我的存儲引擎。前兩個「CREATE」語句正常工作。MYSQL外鍵錯誤：150無法創建表

我需要做些什麼改變才能使「CREATE TABLE Class和CREATE TABLE Enroll」部分起作用？

CREATE TABLE Student (
    stuId VARCHAR(6), 
    lastName VARCHAR(20) NOT NULL, 
    firstName VARCHAR(20) NOT NULL, 
    major VARCHAR(10), 
    credits FLOAT(3) DEFAULT 0, 
    CONSTRAINT Student_stuId_pk PRIMARY KEY (stuId), 
    CONSTRAINT Student_credits_cc CHECK ((credits>=0) AND (credits < 150))); 

CREATE TABLE Faculty (
    facId VARCHAR(6), 
    name VARCHAR(20) NOT NULL, 
    department VARCHAR(20), 
    rank VARCHAR(10), 
    CONSTRAINT Faculty_facId_pk PRIMARY KEY (facId)); 

CREATE TABLE Class (
    classNumber VARCHAR(8), 
    facId VARCHAR(6) NOT NULL, 
    schedule VARCHAR(8), 
    room VARCHAR(6), 
    CONSTRAINT Class_classNumber_pk PRIMARY KEY (classNumber), 
    CONSTRAINT Class_facId_fk FOREIGN KEY (facId) REFERENCES Faculty 
     (facId) ON DELETE SET NULL, 
    CONSTRAINT Class_schedule_room_uk UNIQUE (schedule, room)); 

CREATE TABLE Enroll (
    stuId VARCHAR(6), 
    classNumber VARCHAR(8), 
    grade VARCHAR(2), 
    CONSTRAINT Enroll_classNumber_stuId_pk PRIMARY KEY 
     (classNumber, stuId), 
    CONSTRAINT Enroll_classNumber_fk FOREIGN KEY (classNumber) 
     REFERENCES Class (classNumber) ON DELETE CASCADE, 
CONSTRAINT Enroll_stuId_fk FOREIGN KEY (stuId) REFERENCES Student 
(stuId)ON DELETE CASCADE);

下面是完整的命令和錯誤：

mysql> CREATE TABLE Class (classNumber VARCHAR(8), facId VARCHAR(6) NOT NULL, schedule VARCHAR(8), room VARCHAR(6), CONSTRAINT Class_classNumber_pk PRIMARY KEY (classNumber), CONSTRAINT Class_facId_fk FOREIGN KEY (facId) REFERENCES Faculty (facId) ON DELETE SET NULL, CONSTRAINT Class_schedule_room_uk UNIQUE (schedule, room)); 
ERROR 1005 (HY000): Can't create table 'university.Class' (errno: 150)

來源

2013-09-26 tbenz9

這可能是因爲facId表「類」設置爲NOT NULL，但表「教師」 facId是不是？ – andrewb

我試着在Faculty表中添加「NOT NULL」，並且在其他兩個命令中沒有區別。感謝您的想法，但不幸的是它並沒有解決我的問題。 – tbenz9

可能的重複：[Mysql創建表與多個外鍵刪除設置null]（http://stackoverflow.com/questions/15880070/mysql-create-table-with-multiple-foreign-key-on-delete-set- null） – aaron