Question

我收到ERROR 1215（HY000）：无法添加外键约束错误：外键（locationID）引用位置（locationID）。当我发表评论时，查询没有问题

我似乎无法找到我检查拼写错误的问题，notepad ++在两个语句中都突出显示“Location”和“locationID”。他们也是varchar(3)。

create table Location 
(
    warehouseID varchar(3),
    locationID varchar(3),
    Aisle int,
    Shelf int,
    Bin int,
    capacity Double,
    Primary Key (warehouseID,locationID),
    Foreign Key (warehouseID) references Warehouse(warehouseID)
) Engine = InnoDB;

create table Prod_Location 
(
    warehouseID varchar(3),
    locationID varchar(3),
    productNum int,
    quantityOnHand int,
    Foreign Key (warehouseID) references Warehouse(warehouseID),
    Foreign Key (productNum) references Product(productNum),
    Foreign Key (locationID) references Location(locationID),
    Primary Key (warehouseID, locationID, productNum)
) Engine = InnoDB;

谢谢。

编辑：完整代码

create database WareMart30119267;
use WareMart30119267;

create table Department (
    dptNumber int Auto_Increment,
    dptName varchar(20),
    Primary Key (dptNumber))
    Engine = InnoDB;

create table Product (
    productNum int Auto_Increment,
    description varchar(30),
    packSize int,
    Price Decimal(10,2),
    dptNumber int,
    Primary Key (productNum),
    Foreign Key (dptNumber) references Department(dptNumber))
    Engine = InnoDB;

create table CLient (
    clientNum int Auto_Increment,
    clientName varchar(40),
    Primary Key (clientNum))
    Engine = InnoDB;


create table Client_Address (
    clientNum int Auto_Increment,
    addressType varchar(1),
    street varchar(20),
    city varchar(3),
    state varchar(3),
    postcode varchar(4),
    Primary Key (clientNum, addressType),
    Foreign Key (clientNum) references Client(clientNum))
    Engine = InnoDB;

create table Stock_Request (
    requestNum int Auto_Increment,
    requestDate date,
    clientNum int,
    Primary Key (requestNum),
    Foreign Key (clientNum) references Client(clientNum))
    Engine = InnoDB;

create table Request_List (
    requestNum int,
    productNum int,
    qtyRequested int,
    Primary Key (requestNum, productNum),
    Foreign Key (requestNum) references Stock_Request(requestNum),
    Foreign Key (productNum) references Product(productNum))
    Engine = InnoDB;

create table Warehouse (
    warehouseID varchar(3),
    street varchar(20),
    city varchar(15),
    state varchar(3),
    postcode varchar(4),
    managerID int,
    Primary Key (warehouseID))
    Engine = InnoDB;

create table Location (
    warehouseID varchar(3),
    locationID varchar(3),
    Aisle int,
    Shelf int,
    Bin int,
    capacity Double,
    Primary Key (warehouseID, locationID),
    Foreign Key (warehouseID) references Warehouse(warehouseID))
    Engine = InnoDB;

create table Employee (
    staffID int Auto_Increment,
    surname varchar(20),
    firstName varchar(15),
    dob date,
    street varchar(20),
    city varchar(15),
    state varchar(3),
    postcode varchar(4),
    salary Decimal(19,4),
    warehouseID varchar(3),
    supervisedBy int,
    Primary Key (staffID),
    Foreign Key (supervisedBy) references Employee(staffID))
    Engine = InnoDB;
/*Add Foreign Keys to Warehouse and Employee */

alter table Warehouse
    add Foreign Key (managerID) references Employee(staffID);

alter table Employee
    add Foreign Key (warehouseID) references Warehouse(warehouseID); 


create table Prod_Location (
    warehouseID varchar(3),
    locationID varchar(3),
    productNum int,
    quantityOnHand int,
    Foreign Key (warehouseID) references Warehouse(warehouseID),
    Foreign Key (productNum) references Product(productNum),
    Foreign Key (locationID) references Location(locationID),
    Primary Key (warehouseID,locationID,productNum))
    Engine = InnoDB;

create table Picking_List (
    warehouseID varchar(3),
    locationID varchar(3),
    productNum int,
    requestNum int,
    quantityPicked int,
    datePicked date,
    pickerStaffID int,
    Primary Key (warehouseID, locationID, productNum, requestNum),
    /* Foreign Key (warehouseID) references Warehouse(warehouseID), */
    Foreign Key (locationID, warehouseID) references Location(locationID, warehouseID),
    Foreign Key (productNum) references Product(productNum),
    Foreign Key (requestNum) references Stock_Request(requestNum))
    Engine = InnoDB;

我现在觉得愚蠢，答案是在主键中移动仓库ID和locationID所以它就像这样

create table Location (
warehouseID varchar(3),
locationID varchar(3),
Aisle int,
Shelf int,
Bin int,
capacity Double,
Primary Key (locationID, warehouseID),
Foreign Key (warehouseID) references Warehouse(warehouseID))
Engine = InnoDB;

我不知道为什么订单有所不同，但它修正了错误。

Answer 1

location上的主键被定义为复合键：

Primary Key (warehouseID,locationID),

虽然您试图通过其中一个组件将Prod_Location中的此引用作为外键：

Foreign Key (locationID) references Location(locationID)

您需要将外键更改为与引用键的所有字段合成：

Foreign Key (warehouseID, locationID) references Location(warehouseID, locationID)

或者，或者，将位置的主键更改为简单，例如，只是locationID

修改完整架构发布后我很抱歉 - 复合键的顺序很重要 - 您需要在外键引用中保持主键定义的相同顺序，即(warehouseID, locationID)。

还需要对Location中的Picking_List的复合外键执行此操作。

此外，由于clientNum是表Client_Address中的外键返回客户端，因此它本身不应声明为Auto_Increment，因为它必须与{{1}保持同步并在代码中明确分配。

复合外键的一个常见问题是直接引用和连接到终极组件键表的诱惑，而不是通过复合键引用链接表。我认为Client和Prod_Location之间通过warehouseId的直接关系可能就是一个例子。

SqlFiddle here

Answer 2

从Pro_Location表中删除主键：

create table Location (
    warehouseID varchar(3),
    locationID varchar(3),
    Aisle int,
    Shelf int,
    Bin int,
    capacity Double,
    Primary Key (warehouseID,locationID),
    Foreign Key (warehouseID) references Warehouse(warehouseID))
    Engine = InnoDB;

create table Prod_Location (
    warehouseID varchar(3),
    locationID varchar(3),
    productNum int,
    quantityOnHand int,
    Foreign Key (warehouseID) references Warehouse (warehouseID),
    Foreign Key (productNum) references Product (productNum),
    Foreign Key (locationID) references Location (locationID)
    Engine = InnoDB;

Answer 3

我现在觉得愚蠢，答案是在主键中移动仓库ID和locationID所以它就像这样

create table Location (
warehouseID varchar(3),
locationID varchar(3),
Aisle int,
Shelf int,
Bin int,
capacity Double,
Primary Key (locationID, warehouseID),
Foreign Key (warehouseID) references Warehouse(warehouseID))
Engine = InnoDB;

我不知道为什么订单有所不同但它修正了错误。

ERROR 1215（HY000）：无法添加外键约束，我检查了语法和拼写错误

3 个答案: