我有多個表,它們似乎都很好,但有一個表,我試圖創建,但它不會工作,因爲我繼續得到Error1005 "Foreign key constraint is incorrectly formed"
。不能將外鍵添加到mysql
這是兩張表格。我不知道什麼似乎是問題。
CREATE TABLE Patient(
ID INT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE,
Name VARCHAR(255) NOT NULL,
Age TINYINT UNSIGNED,
Sex VARCHAR(10),
Contact INT(11),
Email TEXT(2083),
PRIMARY KEY(ID)
);
CREATE TABLE Appointments (
Appointment_No INT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE,
Name VARCHAR(255) NOT NULL,
Contact INT(11),
Date DATE NOT NULL,
Time TIME NOT NULL,
Reason TEXT(2083),
PRIMARY KEY(Appointment_No),
FOREIGN KEY (Name, Contact) REFERENCES Patient (Name, Contact)
);
請閱讀[外鍵](https://dev.mysql.com/doc/refman/5.6/en/create-table-foreign-keys.html)和[3NF](https:// en。 wikipedia.org/wiki/Third_normal_form) –