这个 create table 语句有什么问题? [英] What is wrong with this create table statement?

问题描述

我目前正在为学校项目编写数据库.我在 xampp 上使用 MySQL 并尝试将此表添加到我的数据库中.我的 SQL 语法仍然不是 100%，这里有一个错误，我似乎无法弄清楚:

Im currently writing a database for a school project. Im using MySQL on xampp and trying to add this table to my database. Im still not 100% on my SQL syntax and theres an error here I cannot seem ti figure out:

CREATE TABLE photoDB(
    U_id INT UNSIGNED NOT NULL FOREIGN KEY REFERENCES userDB(U_id),
    P_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    C_id INT UNSIGNED NOT NULL FOREIGN KEY REFERENCES table_comments(C_id),

    PhotoName VARCHAR(50),
    Description TEXT NOT NULL,
    File VARCHAR,
    Views BIGINT UNSIGNED,
    Rep DOUBLE (100000, 2),
    UploadDate DATETIME,
    EditDate DATETIME,
    EditVersion INT UNSIGNED,
    LatestEditVerion INT UNSIGNED

    );

我尝试创建的所有表都存在同样的问题.

Im having the same issue with all of the tables Im trying to create.

错误信息如下:

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FOREIGN KEY REFERENCES userDB(U_id), P_id INT UNSIGNED NOT NULL AUTO_INCREMENT ' at line 2

提前致谢

推荐答案

之前的答案都是正确的.您还有其他问题(例如，您不能拥有那么大的 DOUBLE；最大 = 255).

The previous answers are true. You've got other problems, too (e.g. you can't have a DOUBLE that big; max = 255).

你有问题，伙计.

这是一个简单的例子，也许你可以扩展.它有两个表，它们之间是多对多的关系.连接表有两个外键.它适用于 MySQL - 我刚刚创建了一个数据库并添加了这些表.

Here's a simple example that perhaps you can extend. It has two tables with a many-to-many relationship between them. The join table has two foreign keys. It works in MySQL - I just created a database and added these tables.

use stackoverflow;

create table if not exists stackoverflow.product
(
    product_id int not null auto_increment,
    name varchar(80) not null,
    primary key(product_id)
);

create table if not exists stackoverflow.category
(
    category_id int not null auto_increment,
    name varchar(80) not null,
    primary key(category_id)
);

create table if not exists stackoverflow.product_category
(
    product_id int,
    category_id int,
    primary key(product_id, category_id),
    constraint product_id_fkey
        foreign key(product_id) references product(product_id)
        on delete cascade
        on update no action,
    constraint category_id_fkey
        foreign key(category_id) references category(category_id)
        on delete cascade
        on update no action
);

insert into stackoverflow.product(name) values('teddy bear');
insert into stackoverflow.category(name) values('toy');
insert into stackoverflow.product_category
    select p.product_id, c.category_id from product as p, category as c
    where p.name = 'teddy bear' and c.name = 'toy';

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