Question

我正在尝试创建一个带有删除/更新约束的多个外键的数据库，但是我得到了一个带有以下sql脚本的错误代码1005：

CREATE TABLE Worker (
 WorkerID smallint auto_increment,
 WorkerType  varchar(45) NOT NULL,
 WorkerName  varchar(45) NOT NULL,
 Position    varchar(45) NOT NULL,
 TaxFileNumber int NOT NULL,
 Address    varchar(100) ,
 Phone      varchar(20) ,
 SupervisorID  smallint ,
 PRIMARY KEY (WorkerID),
 FOREIGN KEY (SupervisorID) REFERENCES Worker(WorkerID)
    ON DELETE SET NULL
    ON UPDATE CASCADE
)Engine=InnoDB;

CREATE TABLE Grape (
    GrapeID smallint NOT NULL,
    GrapeType varchar(45) NOT NULL,
    JuiceConversionRatio int,
    StorageContainer ENUM('Stainless Steel Tank','Oak Barrel'),
    AgingRequirement int,
    PRIMARY KEY (GrapeID)
)Engine=InnoDB;

CREATE TABLE Vineyard (
    VineyardID smallint auto_increment,
    VineyardName VARCHAR(45) NOT NULL,
    FarmerID    smallint NOT NULL,
    GrapeID smallint NOT NULL,
    ComeFrom    varchar(45) NOT NULL,
    HarvestedAmount int,
    RipenessPercent int,
    PRIMARY KEY (VineyardID),
    FOREIGN KEY (FarmerID) REFERENCES Worker(WorkerID)
        ON DELETE SET NULL
        ON UPDATE CASCADE,
    FOREIGN KEY (GrapeID) REFERENCES Grape(GrapeID)
        ON DELETE SET NULL
        ON UPDATE CASCADE
)Engine=InnoDB;

错误代码表示无法创建Vineyard表，我只想知道使用删除/更新控制创建多个外键的正确格式。

Answer 1

您的外键规则为ON DELETE SET NULL，但您的列定义为NOT NULL。

更改列定义并删除NOT NULL部分或覆盖外键规则。这有效：

CREATE TABLE Vineyard (
    VineyardID smallint auto_increment,
    VineyardName VARCHAR(45) NOT NULL,
    FarmerID    smallint,
    GrapeID smallint,
    ComeFrom    varchar(45) NOT NULL,
    HarvestedAmount int,
    RipenessPercent int,
    PRIMARY KEY (VineyardID),
    FOREIGN KEY (FarmerID) REFERENCES Worker(WorkerID)
        ON DELETE SET NULL
        ON UPDATE CASCADE,
    FOREIGN KEY (GrapeID) REFERENCES Grape(GrapeID)
        ON DELETE SET NULL
        ON UPDATE CASCADE
)Engine=InnoDB;

SQLFiddle demo

Answer 2

尝试使用没有外键的create table（innoDB enginer）并使用update table with constraint语法，例如：

ALTER TABLE `vineyard`
        ADD CONSTRAINT `relation_farmer_has_many_vineyards`
            FOREIGN KEY (`farmer_id`)
            REFERENCES `worker` (`worker_id`)
            ON DELETE SET NULL
            ON UPDATE CASCADE;

<强>参考：


http://dev.mysql.com/doc/refman/5.6/en/innodb-foreign-key-constraints.html

特技：不建议在行为与正在使用的操作系统不同的表的名称中使用大写字母（或驼峰大小写）：

http://dev.mysql.com/doc/refman/5.1/en/identifier-case-sensitivity.html

Answer 3

访问：

empty(sql:variable("@Value"))

>  - &lt;
<  - &gt;
&  - &amp;
'  - &#039;
'' - &#034;

Answer 4

访问：

http://dev.mysql.com/doc/refman/5.5/en/innodb-foreign-key-constraints.html

CREATE TABLE `ffxi_characterJob` (
`serverID` int(11) NOT NULL,
`userid` int(10)unsigned NOT NULL,
`characterName` varchar(255) NOT NULL,
`jobAbbr` char(4) NOT NULL,
`jobLevel` int(11) default '0',
PRIMARY KEY (`serverID`,`userid`,`characterName`,`jobAbbr`),
INDEX (`jobAbbr`),
CONSTRAINT FOREIGN KEY (`serverID`,`userid`,`characterName`) REFERENCES `ffxi_characters` (`serverID`,`userid`,`characterName`) 
ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT FOREIGN KEY (`jobAbbr`) REFERENCES `ffxi_jobType` (`jobAbbr`) ON DELETE CASCADE ON UPDATE CASCADE
) TYPE=InnoDB;

Mysql在删除集上使用多个外键创建表

4 个答案: