mysql - ERROR 1451 无法从父表中删除记录

Question

嘿伙计们，我想删除一条记录。但是由于外键约束不允许我

我试图执行的操作是（所有卡号都是假的）

DELETE FROM payment_method
WHERE card_no = 42218345;

表结构：

CREATE TABLE  payment_details  (
   card_no  int(8) NOT NULL,
   customer_id  int(50)  NOT NULL AUTO_INCREMENT,
   CVV  int(3) NOT NULL,
   card_type  ENUM ('Visa', 'Amex', 'American Express', 'Mastercard') NOT NULL,
   expiry_date  DATE NOT NULL,
   PRIMARY KEY(card_no),
   KEY customer_idfk1 (customer_id),
   CONSTRAINT customer_idfk1 FOREIGN KEY (customer_id) REFERENCES customers (customer_id) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8

和

CREATE TABLE  customers  (
   customer_id  int(50)  NOT NULL AUTO_INCREMENT,
   fname  varchar(20) NOT NULL,
   lname  varchar(20) NOT NULL,
   dateOfBirth date NOT NULL,
   address  varchar(30) NOT NULL,
   city  varchar(20) NOT NULL,
   county  ENUM('Armagh','Carlow','Cavan','Clare','Cork','Derry','Donegal','Down','Dublin','Fermanagh','Galway','Kerry','Kildare','Kilkenny','Laois','Leitrim','Limerick','Longford','Louth','Mayo','Meath','Monaghan','Offaly','Roscommon','Sligo','Tipperary','Tyrone','Waterford','Westmeath','Wexford','Wicklow') NOT NULL,
   phone  int(10) NOT NULL,
   email  varchar(20) NOT NULL,
   payment_method  ENUM ('Visa', 'Amex', 'Cash', 'American Express', 'Mastercard') NOT NULL,
   valid_licence varchar(5) NOT NULL,
   status  varchar(10),
   PRIMARY KEY (customer_id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

错误是：

1451 - 无法删除或更新父行：外键约束失败（g00337857abu. payment_details, CONSTRAINTcustomer_idfk1

外键 ( customer_id) 参考customers( customer_id))

有谁知道为什么它不允许我删除这条记录..

我发现了第一个错误

现在我试图从客户表中删除

DELETE FROM customers
WHERE customer_id = 1

错误 - #1451 - 无法删除或更新父行：外键约束失败 ( g00337857abu. payment_details, CONSTRAINT customer_idfk1FOREIGN KEY ( customer_id) REFERENCES customers ( customer_id))

标签： mysql