How to add foreign keys to Mysql data table? (Pictures + Videos)

This article mainly introduces how to add foreign keys to mysql data table.

So in the previous article [How to create foreign keys in mysql database? ] has introduced to you the method of mysql creating foreign keys, that is, mysql setting foreign keys when creating tables.

If you want to know more about mysql foreign keys, you can also refer to these two articles:

[What are Mysql foreign keys? What are the uses? 】

【How to use mysql foreign keys? Introduction to the use of foreign keys in Mysql database 】

Let’s use a simple example to give you a detailed introduction on how to add foreign keys to mysql data tables.

First open and query our existing database through the command line tool

Then select use test this database.

Then query the existing data table.

Execute the following command statement to add foreign keys. Here we add a foreign key to the stu table.

Note, The main syntax for adding foreign keys:

alter table +表名+add
[constanint + 外键名字]+
foreign key(外键字段) +
references 外部表名(主键字段);

Finally we can use Navicat (database management tool) to be more intuitive Check whether the foreign key is added successfully.

As shown in the figure, the foreign key, that is, the c_id foreign key field, has been successfully added to the stu table.

Note: Navicat is a set of fast, reliable and relatively cheap database management tools, designed to simplify database management and reduce system management costs. And is built with an intuitive graphical user interface that allows you to create, organize, access and share information in a secure and simple way.

This article is about the specific method of adding foreign keys to Mysql data table. It is simple and easy to understand. I hope it will be helpful to friends in need!

So about the Navicat database management tool mentioned in the article, friends who are interested can also read the previous related Navicat articles:

[How about Navicat Import and export sql files? 】

If you want to know more about mysql, you can follow the PHP Chinese website mysql video tutorial, everyone is welcome to refer to and learn!

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