使用外键在mysql中工作(Working in mysql with foreign keys)

 我想用外键创建一个mysql数据库。 但是当我插入一些测试数据时，我注意到当我查看表tblcontact和tbladdress时，我的外键为null。 我知道这是一个基本问题，但你能提出一些建议吗？ 
 
CREATE TABLE tblCustomers (
customerID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
vat VARCHAR(30) NOT NULL,
customerVisible varchar(1) NOT NULL DEFAULT 'T'
); 


CREATE TABLE tblContact (
contactID INT NOT NULL  AUTO_INCREMENT PRIMARY KEY,
email VARCHAR(100),
phone VARCHAR(100),
customerID int,
CONSTRAINT FK_customerID FOREIGN KEY (customerID) REFERENCES tblCustomers(customerID) 
);

CREATE TABLE tblAddress (
addressID INT NOT NULL  AUTO_INCREMENT PRIMARY KEY,
street VARCHAR(100),
houseNumber VARCHAR(15),
city VARCHAR (100),
country VARCHAR (100),
customerID int,
CONSTRAINT FK_customerIDa  FOREIGN KEY (customerID) REFERENCES tblCustomers(customerID)
);

 INSERT INTO tblCustomers (firstname, lastname,vat) VALUES ("John","Doe","UV45856855");
INSERT INTO tblContact (email, phone) VALUES ("0000001","Johndoe@gmail.com");
INSERT INTO tblAddress (street,housenumber,city,country) VALUES ("berkenlaan","1a","Harelbeke","Belgie");

I want to create a mysql database with foreign keys. But when i insert some test data i notice that when i look in tables tblcontact and tbladdress my foreign key is null. I know its a basic question but can you give some suggestions?
 
CREATE TABLE tblCustomers (
customerID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
vat VARCHAR(30) NOT NULL,
customerVisible varchar(1) NOT NULL DEFAULT 'T'
); 


CREATE TABLE tblContact (
contactID INT NOT NULL  AUTO_INCREMENT PRIMARY KEY,
email VARCHAR(100),
phone VARCHAR(100),
customerID int,
CONSTRAINT FK_customerID FOREIGN KEY (customerID) REFERENCES tblCustomers(customerID) 
);

CREATE TABLE tblAddress (
addressID INT NOT NULL  AUTO_INCREMENT PRIMARY KEY,
street VARCHAR(100),
houseNumber VARCHAR(15),
city VARCHAR (100),
country VARCHAR (100),
customerID int,
CONSTRAINT FK_customerIDa  FOREIGN KEY (customerID) REFERENCES tblCustomers(customerID)
);

 INSERT INTO tblCustomers (firstname, lastname,vat) VALUES ("John","Doe","UV45856855");
INSERT INTO tblContact (email, phone) VALUES ("0000001","Johndoe@gmail.com");
INSERT INTO tblAddress (street,housenumber,city,country) VALUES ("berkenlaan","1a","Harelbeke","Belgie");

原文：https://stackoverflow.com/questions/29181369