简体繁体 English

表中有多个主键

[英]Multiple primary keys in table

原文 2014-06-04 11:56:46 0 1 mysql/ database/ database-design/ innodb

A friend of mine just sent me an image of his new api database design. 我的一个朋友刚给我发了一张他新的api数据库设计的图片。

When I saw it, I noticed that his user table had three primary ids. 当我看到它时，我注意到他的用户表有三个主要ID。

I actually thought this wouldn't be possible. 我实际上认为这是不可能的。

It got me thinking... Is it okay to do this? 它让我思考......这样做可以吗？ As long as each column is unique? 只要每列都是唯一的？

I can't seem to find a reason not to do this, except the id is not primary if there are more than one. 我似乎无法找到不这样做的理由，除非id不是主要的，如果有多个。

Is this a bad database design? 这是一个糟糕的数据库设计吗？ And why? 为什么？

1 个解决方案

There should be only one column(s) designated as the PRIMARY KEY per table and most DB's will disallow usage of multiple PRIMARY KEYS. 每个表应该只有一个列被指定为PRIMARY KEY，并且大多数DB将禁止使用多个PRIMARY KEYS。 Note that a PRIMARY KEY can span multiple columns. 请注意，PRIMARY KEY可以跨越多列。 Use UNIQUE for other column(s) that require unique values. 对于需要唯一值的其他列，请使用UNIQUE。 UNIQUE keys can also be used in foreign key relationships. UNIQUE键也可用于外键关系。

创建具有多个主键的联接表？ - Creating Join table with multiple Primary Keys?

如何拥有一个包含多个主键的表？ - How to have a table with multiple primary keys?

一个表可以有多个主键吗？ - Can a table have multiple Primary keys?

如何在作为主键和候选键的表中引用多个外键？ - How to reference multiple foreign keys in a table that is a primary key and candidate keys?

MySQL表主键 - MySQL Table primary keys

多个主/外键 - Multiple Primary/Foreign Keys

Doctrine 2多个主键 - Doctrine 2 multiple primary keys

Mysql：如何创建一个包含多个主键的表？ - Mysql: How do you create a table with multiple primary keys?

mysql表中的多个外键指向相同的主键 - mysql Multiple Foreign Keys in a Table to the Same Primary Key

具有链接到同一主键的多个外键的表 - Table with multiple foreign keys linking to the same primary key

暂无

暂无

声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.

相关问题 创建具有多个主键的联接表？ - Creating Join table with multiple Primary Keys? 如何拥有一个包含多个主键的表？ - How to have a table with multiple primary keys? 一个表可以有多个主键吗？ - Can a table have multiple Primary keys? 如何在作为主键和候选键的表中引用多个外键？ - How to reference multiple foreign keys in a table that is a primary key and candidate keys? MySQL表主键 - MySQL Table primary keys 多个主/外键 - Multiple Primary/Foreign Keys Doctrine 2多个主键 - Doctrine 2 multiple primary keys Mysql：如何创建一个包含多个主键的表？ - Mysql: How do you create a table with multiple primary keys? mysql表中的多个外键指向相同的主键 - mysql Multiple Foreign Keys in a Table to the Same Primary Key 具有链接到同一主键的多个外键的表 - Table with multiple foreign keys linking to the same primary key

相关标签

粤ICP备18138465号 © 2020-2024 STACKOOM.COM