Mysql 如何创建包含两个主键和两个外键的表?
Mysql抱怨语法有问题 期望的结果:让表“机器部件”使用“机器ID”和“部件ID”作为两个主键(都是外键)。类似这样的内容-Mysql 如何创建包含两个主键和两个外键的表?,mysql,foreign-keys,primary-key,composite-primary-key,Mysql,Foreign Keys,Primary Key,Composite Primary Key,Mysql抱怨语法有问题 期望的结果:让表“机器部件”使用“机器ID”和“部件ID”作为两个主键(都是外键)。类似这样的内容- create table Machine ( Machine_ID int primary key, Machine_Name varchar(30) Machine_Title varchar(30) ) create table Part ( Part_ID int primary key, Part_Name varchar(30), Part_Des
create table Machine
(
Machine_ID int primary key,
Machine_Name varchar(30)
Machine_Title varchar(30)
)
create table Part
(
Part_ID int primary key,
Part_Name varchar(30),
Part_Description varchar(30)
)
//How do I make this table below?
create table Machine-Part
(
Machine_ID int foreign key references (Machine.Machine_ID),
Part_ID int foreign key references (Part.Part_ID)
Factory_Note varchar(30);
)
您可以在这些页面上找到所有信息:
CREATE TABLE Machine(
Machine_ID INT PRIMARY KEY,
Machine_Name VARCHAR(30),
Machine_Title VARCHAR(30)
)
ENGINE = INNODB;
CREATE TABLE Part(
Part_ID INT PRIMARY KEY,
Part_Name VARCHAR(30),
Part_Description VARCHAR(30)
)
ENGINE = INNODB;
create table `Machine-Part`(
Machine_ID int,
Part_ID int,
Factory_Note varchar(30),
CONSTRAINT fk_Machine_ID FOREIGN KEY (Machine_ID) REFERENCES Machine(Machine_ID),
CONSTRAINT fk_Part_ID FOREIGN KEY (Part_ID) REFERENCES Part(Part_ID)
)
ENGINE = INNODB;
链接表几乎总是需要一个反向索引ENGINE=INNODB是什么;do/mean?目前只有INNODB引擎支持外键。我明确指定了这个值。使用这些查询查看MySQL服务器的默认存储引擎:显示“default_storage_engine”之类的变量;或显示“table_type”之类的变量;
create table Machine-Part
(
Machine_ID int NOT NULL ,
Part_ID int NOT NULL ,
Factory_Note varchar(30) NULL,
PRIMARY KEY (Machine_ID, Part_ID),
UNIQUE INDEX (Part_ID, Machine_ID),
foreign key (Machine_ID) references (Machine.Machine_ID),
foreign key (Part_ID) references (Part.Part_ID)
)