mysql - 在 MySQL 5.5 中创建三个相关表

Question

Use snhpinventorytest;
CREATE TABLE Persons (
    PersonID INT(11) unsigned NOT NULL auto_increment,
        PRIMARY KEY (PersonID),
    FirstName Varchar (50), 
    Lastname varchar(50)   
)   ENGINE=INNODB;

Use snhpinventorytest;
CREATE TABLE if not exists Locations (
    LocationID INT(11) UNSIGNED NOT NULL auto_increment,
    PRIMARY KEY (LocationID),
    PersonID int(11) unsigned,
        INDEX PersonID_IDX (PersonID),
    BuildingName varchar(50),
    LocationType varchar(50),
    RoomNumber varchar (20),
        FOREIGN KEY (FK_PersonID) REFERENCES Person(PersonID)
            ON DELETE CASCADE
            ON UPDATE CASCADE
)  ENGINE=INNODB;

Use snhpinventorytest;
CREATE TABLE if not exists assets (
    AssetID INT(11)  UNSIGNED NOT NULL auto_increment,
     PRIMARY KEY (AssetID),
     PersonID int(11) unsigned,
        INDEX PersonID_IDX (PersonID),
     FOREIGN KEY (FK_PersonID) REFERENCES Person(PersonID)
        ON DELETE CASCADE
        ON UPDATE CASCADE
)   Engine=INNODB;

我是 MySQL 新手。使用工作台 6.2我可以创建 Person 表，但不能创建 Locations 或 Assets 表。
1005 和 (errno 150) 建议表示赞赏。我认为我围绕外键的陈述顺序可能不正确，但不确定如何？

Answer 1

您必须更改代码才能使其正常工作。

您需要一个 CONSTRAINT 名称并使其独一无二。然后你需要提供正确的 FOREIGN KEY 而不是任何名称。例如 FOREIGN KEY (FK_PersonID) 应该是 FOREIGN KEY (PersonID)

还有，您不需要使用 USE snhpinventorytest; 3 次 :) 您可以使用一次。

希望对你有帮助

试试这段代码

USE snhpinventorytest;
CREATE TABLE Persons (
    PersonID INT(11) unsigned NOT NULL  auto_increment,
        PRIMARY KEY (PersonID),
    FirstName Varchar (50), 
    Lastname varchar(50)   
)   ENGINE=INNODB;

CREATE TABLE locations (
 LocationID int(11) unsigned NOT NULL AUTO_INCREMENT,
 PersonID int(11) unsigned DEFAULT NULL,
 BuildingName varchar(50) DEFAULT NULL,
 LocationType varchar(50) DEFAULT NULL,
 RoomNumber varchar(20) DEFAULT NULL,
 PRIMARY KEY (LocationID),
 KEY PersonID_IDX (PersonID),
 CONSTRAINT FK_PersonID1 FOREIGN KEY (PersonID) REFERENCES persons (PersonID) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS assets (
    AssetID INT(11)  UNSIGNED NOT NULL auto_increment,
     PRIMARY KEY (AssetID),
     PersonID int(11) unsigned,
        INDEX PersonID_IDX (PersonID),
     CONSTRAINT FK_PersonID2 FOREIGN KEY (PersonID) REFERENCES Persons(PersonID)
        ON DELETE CASCADE
        ON UPDATE CASCADE
)   Engine=INNODB;